23 June 2015

Mechanical Turk: Amazon's new charges are not the biggest problem

Twitter was buzzing, or something, this morning, with the news that Amazon is going to change the commission rates that it charges researchers who use Mechanical Turk (henceforth: MTurk) participants to take surveys, quizzes, personality tests, etc.

(This blog post contains some MTurk jargon.  My previous post was way too long because I spent too much time summarising what someone else had written, so if you don't know anything about MTurk concepts, read this.)

The changes to Amazon's rates, effective July 21, 2015, are listed here, but since that page will probably change after July, I took a screenshot:

Here's what this means.  Currently, if you hire 100 people to fill in your survey and want to give them $1 each, you pay Amazon $110 for "regular" workers and $130 for "Masters".  Under the new pricing scheme, this will be $140 and $145, respectively.  That's an increase of 27.3% and 11.5%, respectively.  (I'm assuming, first, that the wording about "10 or more assignments" means "10 or more instances of the HIT being executed, not necessarily by the same worker", and second, that any psychological survey will need more than 10 assignments.)

Twitter users were quite upset about this.  Someone portrayed this as a "400% increase", which is either a typo, or a miscalculation (Amazon's commission for "regular" workers is going from 10% to 40%, which even expressed as "$10 to $40 on a $100 survey" is actually a 300% increase), or a misunderstanding (the actual increase in cost for the customer is noted in the previous paragraph).  People are talking of using this incident as a reason to start a new, improved platform, possibly creating an international participant pool.

Frankly, I think there is a lot of heat and not much light being generated here.

First, researchers are going to have to face up to the fact that by using MTurk, they are typically exploiting sub-minimum wage labour.  (There are, of course, honourable exceptions, who try to ensure that online survey takers are fairly remunerated.)  The lowest wage rate I've personally seen in the literature was a study that paid over 100 workers the princely sum of $0.25 each for a task that took 20 minutes to complete.  Either those people are desperately poor, or they are children looking for pocket money, or they are people who just really, really like being involved in research, to an extent that might make some people wonder about selection bias.

I have asked researchers in the past how they felt about this exploitation, and the standard answer has been, "Well, nobody's forcing them to do it".  The irony of social psychologists --- who tend not to like it when someone points out that they overwhelmingly self-identify as liberal and this is not necessarily neutral for science --- invoking essentially the same arguments as exploitative corporations for not paying people adequately for their time, is wondrous to behold.  (It's not unique to academia, though.  I used to work at an international organisation, dedicated to human rights and the rule of law, where some managers who made six-figure tax-free salaries were constantly looking for ways to get interns to do the job of assistants, or have technical specialists agree to work for several months for nothing until funding "maybe" came through for their next contract.)

Second, I have doubts about the validity of the responses from MTurk workers.  Some studies have shown that they can perform as well as college students, although maybe it's best to take on the "Master"-level workers, whose price is only going up 11.5%; and I'm not sure that college students ought to be regarded as the best benchmark [PDF] here.  But there are technical problems, such as issues with non-independence of data [PDF] --- if you put three related surveys out there, there's a good chance that many of the same people may be answering them --- and the population of MTurk workers is a rather strange and unrepresentative bunch of people; the median participant in your survey has already completed 300 academic tasks, including 20 in the past week.  One worker completed 830,000 MTurk HITs in 9 years; if you don't want to work out how many minutes per HIT that represents assuming she worked for 16 hours a day, 365 days a year, here's the answer.  Workers are overwhelmingly likely to come from one of just two countries, the USA and India, presumably because those are the countries where you can get paid in real cash money; MTurk workers in other countries just get credit towards an Amazon gift card (which, when I tried to use it, could only be redeemed on the US site, amazon.com, thus incurring shipping and tax charges when buying goods in Europe).  Maybe this is better than having your participants being all from just one country, but since you don't know what the mix of countries is (unless you specify that the HIT will only be shown in one country), you can't even make claims about the degree of generalisability of your results.

Third, this increase really does not represent all that much money.  If you're only paying $33 to run 120 participants at $0.25, you can probably afford to pay $42.  That $9 increase is less than you'll spend on doughnuts at the office mini-party when your paper gets accepted (but it won't go very far towards building, running, and paying the electricity bill for your alternative, post-Amazon solution).  And let's face it, if these commission rates had been in place from the start, you'd have paid them; the actual increase is irrelevant, just like it doesn't matter when you pay $20 for shipping on a $2 item from eBay if the alternative is to spend $30 with "free" shipping.  All those people tweeting "Goodbye Amazon" aren't really going to switch to another platform.  At bottom, they're just upset because they discovered that a corporation with a monopoly will exploit it, as if they really, really thought that things were going to be different this time (despite everyone knowing that Amazon abuses its warehouse workers and has a history of aggressive tax avoidance).  Indeed, the tone of the protests is remarkable for its lack of direct criticism of Amazon, because that would require an admission that researchers have been complicit with its policies, to an extent that I would argue goes far beyond the average book buyer.  (Disclosure: I'm a hypocrite who orders books or other goods from Amazon about four times a year. I have some good and more bad justifications for that, but basically, I'm not very political, the points made above notwithstanding.)

Bottom line: MTurk is something that researchers can, and possibly (this is not a blog about morals) "should", be able to do without.  Its very existence as a publicly available service seems to be mostly a matter of chance; Amazon doesn't spend much effort on developing it, and it could easily disappear tomorrow.  It introduces new and arguably unquantifiable distortions into research in fields that already have enough problems with validity.  If this increase in prices led to people abandoning it, that might be a good thing.  But my guess is that they won't.



Acknowledgement: Thanks to @thosjleeper for the links to studies of MTurk worker performance.



05 June 2015

Dream on: Playing pinball in your sleep does not make you a better person

(Note: this is more or less my first solo foray into unaided statistical and methodological criticism.  Normally I hitch a ride on the coat-tails of my more experienced co-authors, hoping that they will spot and stop my misunderstandings.  In this case, I haven't asked  anybody to do that for me, so if this post turns out to be utter garbage, I will have only myself to blame.  But it probably won't kill me, so according to the German guy with the fancy moustache, it will make me stronger.)

Among all the LaCour kerfuffle last week, this article by Hu et al. in Science seems to have slipped by with relatively little comment on social media.  That's a shame, because it seems to be a classic example of how fluffy articles in vanity journals can arguably do more damage to the cause of science than outright fraud.

I first noticed Hu et al.'s article in the BBC app on my tablet.  It was the third article in the "World News" section.  Not the Science section, or the Health section (for some reason, the BBC's write-up was done by their Health correspondent, although what the study has to do with health is not clear); apparently this was the third most important news story in the world on May 29, 2015.

Hu et al.'s study ostensibly shows that certain kinds of training can be reinforced by having sounds played to you while you sleep.  This is the kind of thing the media loves.  Who cares if it's true, or even plausible, when you can claim that "The more you sleep, the less sexist and racist you become", something that is not even suggested in the study?  (That piece of crap comes from the same newspaper that has probably caused several deaths down the line by scaremongering about the HPV vaccine; see here for an excellent rebuttal.)  After all, it's in Science (aka "the prestigious journal, Science"), so it must be true, right?  Well, let's see.

Here's what Hu et al. did.  First, they had their participants take the Implicit Association Test (IAT).  The IAT is, very roughly speaking, a measure of the extent to which you unconsciously endorse stereotypically biased attitudes, e.g. (in this case) that women aren't good at science, or Black people are bad.  If you've never taken the IAT, I strongly recommend that you try it (here; it's free and anonymous); you may be shocked by the results, especially if (like almost everybody) you think you're a pretty open-minded, unbigoted kind of person.  Hu et al.'s participants took the IAT twice, and their baseline degree of what I'll call for convenience "sexism" (i.e., the association of non-sciencey words with women's faces; the authors used the term "gender bias", which may be better, but I want an "ism") and "racism" (association of negative words with Black faces) was measured.

Next, Hu et al. had their participants undergo training designed to counter these undesirable attitudes. This training is described in the supplementary materials, which are linked to from the article (or you can save a couple of seconds by going directly here).  The key point was that each form of the training ("anti-sexism" and "anti-racism") was associated with its own sound that was played to the participants when they did something right.  You can find these sounds in the supplementary materials section, or play them directly here and here; my first thought is that they are both rather annoying, having seemingly been taken from a pinball machine, but I don't know if that's likely to have made a difference to the outcomes.

After the training session, the participants retook the IAT (for both sexism and racism), and as expected, performed better.  Then, they took a 90-minute nap.  While they were asleep, one of the sounds associated with their training was selected at random and played repeatedly to each of them; that is, half the participants had the sound from the "anti-sexism" part of the training played to them, and the other half had the sound from the "anti-racism" aspect played to them. The authors claimed that "Past research indicates" that this process leads to reinforcement of learning (although the only reference they provided is an article from the same lab with the same corresponding author).

Now comes the key part of the article.  When the participants woke up from their nap, they took the IAT (again, for both sexism and racism) once more.  The authors claimed that people who were "cued" with the sound associated with the anti-sexism training during their nap further improved their performance on the "women and science" version of the test, but not the "negative attitudes towards Black people" version (the "uncued"training); similarly, those who were "cued" with the sound associated with the anti-racism training became even more unconsciously tolerant towards Black people, but not more inclined to associate women with science.  In other words, the sound that was played to them was somehow reinforcing the specific message that had been associated with that sound during the training period.

Finally, the authors had the participants return to their lab a week later, and take the IAT for both sexism and racism, one more time.  They found that performance had slipped --- that is, people did worse on both forms of the IAT, presumably as the effect of the training wore off --- but that this effect was greater for the "cued" than the "uncued" training topic.  In other words, playing the sound of one form of the training during their nap not only had a beneficial effect on people's implicit, unconscious attitudes (reinforcing their training), but this effect also persisted a whole week later.

So, what's the problem?   Reactions in the media, and from scientists who were invited to comment, concentrated on the potential to save the world from sexism and racism, with a bit of controversy as to whether it would be ethical to brainwash people in their sleep even if it were for such a good cause.  However, that assumes that the study shows what it claims to show, and I'm not at all convinced of that.

Let's start with the size of the study.  The authors reported a total of 40 participants; the supplementary materials mention that quite a few others were excluded, mostly because they didn't enter the "right" phase of sleep, or they reported hearing the cueing sound.  That's just 20 participants in each condition (cued or uncued), which is less than half the number you need to have 80% power to detect that men weigh more than women.  In other words, the authors seem to have found a remarkably faint star with their very small telescope [PDF].

The sample size problem gets worse when you examine the supplemental material and learn that the study was run with two samples; in the first, 21 participants survived the winnowing process, and then eight months later, 19 more were added.  This raises all sorts of questions.  First, there's a risk that something (even it was apparently insignificant: the arrangement of the computers in the IAT test room, the audio equipment used to play the sounds to the participants, the haircut of the lab assistant) changed between the first and second rounds of testing.  More importantly, though, we need to know why the researchers apparently chose to double their sample size.  Could it be because they had results that were promising, but didn't attain statistical significance?  They didn't tell us, but it's interesting to note that in Figures S2 and S3 of the supplemental material, they pointed out that the patterns of results from both samples were similar(*).  That doesn't prove anything, but it suggests to me that they thought they had an interesting trend, and decided to see if it would hold with a fresh batch of participants.  The problem is, you can't just peek at your data, see if it's statistically significant, and if not, add a few more participants until it is.  That's double-dipping, and it's very bad indeed; at a minimum, your statistical significance needs to be adjusted, because you had more than one try to find a significant result. Of course, we can't prove that the six authors of the article looked at their data; maybe they finished their work in July 2014, packed everything up, got on with their lives until February 2015, tested their new participants, and then opened the envelope with the results from the first sample.  Maybe.  (Or maybe the reviewers at Science suggested that the authors run some more participants, as a condition for publication.  Shame on them, if so; the authors had already peeked at their data, and statistical significance, or its absence, is one of those things that can't be unseen.)

The gee-whiz bit of the article, which the cynic in me suspects was at least partly intended for rapid consumption by naive science journalists, is Figure 1, a reasonably-sized version of which is available here.  There are a few problems with the clarity of this Figure from the start; for example, the blue bars in 1B and 1F look like they're describing the same thing, but they're actually slightly different in height, and it turns out (when you read the labels!) that in 1B, the left and right sides represent gender and race bias, not (as in all the other charts) cued and uncued responses.  On the other hand, the green bars in 1E and 1F both represent the same thing (i.e., cued/uncued IAT results a week after the training), as do the red bars in 1D and 1E, but not 1B (i.e., pre-nap cued/uncued IAT results).

Apart from that possible labelling confusion, Figure 1B appears otherwise fairly uncontroversial, but it illustrates that the effect (or at least, the immediate effect) of anti-sexism training is, apparently, greater than that of anti-racism training.  If that's true, then it would have been interesting to see results split by training type in the subsequent analyses, but the authors didn't report this.  There are some charts in the supplemental material showing some rather ambiguous results, but no statistics are given. (A general deficiency of the article is that the authors did not provide a simple table of descriptive statistics; the only standard deviation reported anywhere is that of the age of the participants, and that's in the supplemental material.  Tables of descriptives seem to have fallen out of favour in the age of media-driven science, but --- or "because"? --- they often have a lot to tell us about a study.)

Of all the charts, Figure 1D perhaps looks the most convincing.  It shows that, after their nap, participants' IAT performance improved further (compared to their post-training but pre-sleep results) for the cued training, but not for the uncued training (e.g., if the sound associated with anti-sexism training had been played during their nap, they got better at being non-sexist but not at being non-racist).  However, if you look at the error bars on the two red (pre-nap) columns in Figure 1D, you will see that they don't overlap.  This means that, on average, participants who were exposed to the sound associated with anti-sexism were performing significantly worse on the sexism component of the IAT than the racism component, and vice versa.  In other words, there was more room for improvement on the cued task versus the uncued task, and that improvement duly took place.  This suggests to me that regression to the mean is one possible explanation here.  Also, the significant difference (non-overlapping error bars) between the two red bars means that the authors' random assignment of people to the two different cues (having the "anti-sexism" or "anti-racism" training sound played to them) did not work to eliminate potential bias.  That's another consequence of the small sample size.

Similar considerations apply to Figure 1E, which purports to show that cued "learning" persisted a week afterwards.  Most notable about 1E, however, is what it doesn't show.  Remember, 1D shows the IAT results before and after the nap.  1E uses data from a week after the training, but it doesn't compare the IAT results from a week later with the ones from just after the nap; instead, it compares them with the results from just before the nap.  Since the authors seem to have omitted to display in graphical form the most direct effect of the elapsed week, I've added it here.  (Note: the significance stars are my estimate.  I'm pretty sure the one star on the right is correct, as the error bars just fail to overlap; on the left, there should be at least two stars, but I'm going to allow myself a moment of hyperbole and show three.  In any case, as you'll see in the discussion of Figure 1F, this is all irrelevant anyway.)


So, this extra panel (Figure 1E½?) could have been written up something like this: "Cueing during sleep did not result in sustained counterbias reduction; indeed, the cued bias increased very substantially between postnap and delayed testing [t(37) = something, P = very small], whereas the increase in the uncued bias during the week after postnap testing was considerably smaller [t(37) = something, P = 0.045 or thereabouts]."  However, Hu et al. elected not to report this.  I'm sure they had a good reason for that.  Lack of space, probably.

Combining 1D and 1E, we get this chart (no significance stars this time).  My "regression to the mean" hypothesis seems to find some support here.


Figure 1F shows that Hu et al. have committed a common fallacy in comparing two conditions on the basis of one showing a statistically significant effect and the other not (in fact, they committed this fallacy several times in their article, in their explanation of almost every panel of Figure 1).  They claimed that 1F shows that the effect of cued (versus uncued) training persisted after a week, because the improvement in IAT scores over baseline for the cued training (first blue column versus first green column) was statistically significant, whereas the corresponding improvement for the uncued training (second blue column versus second green column) was not.  Yet, as Andrew Gelman has pointed out in several blog posts with similar titles over the past few years, the difference between “statistically significant” and “not statistically significant” is not in itself necessarily statistically significant.  (He even wrote an article [PDF] on this, with Hal Stern.)  The question of interest here is whether the IAT performance for the topics (sexism or racism) of cued and uncued training, which were indistinguishable at baseline (the two blue columns) was different at the end of the study (the two green columns).  And. as you can see, the error bars on the two green columns overlap substantially; there is no evidence of a difference between them.

One other point to end this rather long post.  Have a look at Figure 2 and the associated description.  Maybe I'm missing something, but it looks to me as if the authors are proudly announcing how they went on a fishing expedition:
Neurophysiological activity during sleep—such as sleep spindles, slow waves, and rapid-eye-movement (REM) duration—can predict later memory performance (17). Accordingly, we explored possible relations between cueing-specific bias reduction and measures of sleep physiology. We found that only SWS × REM sleep duration consistently predicted cueing-specific bias reduction at 1 week relative to baseline (Fig. 2) [r(38) = 0.450, P = 0.005] (25).
They don't tell us how many combinations of parameters they tried to come up with that lone significant result; nor, in the next couple of paragraphs, do they give us any theoretical justification other than handwaving why the product of SWS and REM sleep duration (whose units, the label on the horizontal access of Figure 2 notwithstanding, are "square minutes", whatever that might mean) --- as opposed to the sum of these two numbers, or their difference, or their ratio, or any one of a dozen other combinations --- should be physiologically relevant.  Indeed, selecting the product has the unfortunate effect of making half of the results zero - I count 20 dots that aren't on the vertical axis, for 40 participants.  I'm going to guess that if you remove those zeroes (which surely cannot have any physiological meaning), the regression line is going to be a lot flatter than it is at present.

Bottom line: I have difficulty believing that there is anything to see here.  We can put off the debate about the ethics of subliminally improving people for a while, or at least rest assured that it's likely to remain an entirely theoretical problem.




(*) Incidentally, each red- or green-coloured column in one of the panes of Figure S3 corresponds to approximately five (5) participants.  You can't even detect that men are taller than women with that.

21 May 2015

What to do with people who commit scientific fraud?

Another story of apparent scientific fraud has hit the headlines.  I'm sure that most people who are reading this post will have seen that story and formed their own opinions on it.  It certainly doesn't look good.  And the airbrushing of history has already begun, as you can see by comparing the current state of this page on the website of the MidWest Political Science Association with how it looked back in March 2015 (search for "Fett" and look at the next couple of paragraphs).  Meanwhile, Michael LaCour hastily replaced his CV (which was dated 2015-02-09) with an older version (dated 2014-09-01) that omitted his impressive-looking list of funding sources (see here for the main difference between the two versions); at this writing (2015-05-22 10:37 UTC), his CV seems to be missing entirely from his site.

This rapidly- (aka "hastily-") written post is in response to some tweets calling for fraudsters to be banned from academia for life.  I have a few problems with that.

First, I'm not quite sure what banning someone would mean.  Are they to have "Do Not Hire In Any Academic Context" tattooed on their forehead?  In six languages?  Or should we have a central "Do Not Hire" repository, with DNA samples to prevent false identities (and fingerprints to prevent people impersonating their identical twin)?

Second, most fraudsters don't confess, nor are they subjected to any formal legal process (Diederik Stapel is a notable exception, having both confessed in a book [PDF] and been given a community service penalty, as well as what amounts to a 6-figure fine, by a court in the Netherlands).  As far as I can tell, these people tend to deny any involvement, get fired, disappear for a while, and then maybe turn up a few years later teaching mathematics at a private high school or something, once the publicity has died down and they've massaged their CVs sufficiently.  Should that be forbidden too?  How far do we let our dislike of people who have let us down extend to depriving them of any chance of earning a living in future?

After all, we rehabilitate people who kill other people; indeed, in some cases, we rehabilitate them as academics.  And as the case of Frank Abagnale shows, sometimes a fraudster can be very good at detecting fraud in others.  Perhaps we should give the few fraudsters who confess a shot at redemption.  Sure, we should treat their subsequent discoveries with skepticism, and we probably won't allow them to collect data unsupervised, but by simply casting them out, we miss an opportunity to learn, both about what drove (and enabled) them to do what they did, and how to prevent or mitigate future cases.  We study all kinds of unpleasant things, so why impose this blind spot on ourselves?

Let's face it, nobody likes being the victim of wrongdoing.  When I came downstairs a couple of years ago to find that my bicycle had been stolen from my yard overnight, the one time that I didn't lock it because it was raining so hard when I arrived home that I didn't want to stay out in the rain a second longer to do it, I was all in favour of the death penalty, or at the very least lifelong imprisonment with no possibility of parole, for bicycle thieves.  The inner reactionary in me had come out; I had become the conservative that apparently emerges whenever a liberal gets mugged.  Yet, we know from research (that we have to presume wasn't faked --- ha ha, just kidding!) that more severe punishments don't deter crime, and that what really makes a difference [PDF] is the perceived chance of being caught (and/or sentenced).  And here, academia does a really, really terrible job.

First, our publishing system is, to a first approximation, completely broken.  It rewards style over substance in a systematic way (and Open Access publishing, in and of itself, will not fix this).  As outside observers of any given article, we are fundamentally unable to distinguish between reviewers who insist on more rigour because our work needs more rigour, and those who have missed the point completely; anyone who has had an article rejected from a journal that has also recently published some piece of "obvious" garbage will know this feeling (especially if our article was critical of that same garbage, and seems to be being held to a totally different set of standards [PDF]).

Second, we --- society, the media, the general public, but also scientists among ourselves (I include myself in the set of "scientists" here mostly for syntactic convenience) --- lionize "brilliant" scientists when they discover something, even though that something --- if it's a true scientific discovery --- was surely just sitting there waiting to be discovered. (Maybe this confusion between scientists and inventors will get sorted out one day; I think it's a very fundamental problem. Perhaps we would be better off if Einstein hadn't been so photogenic.) And that's assuming that what the scientist has discovered is even, as the saying goes, "a thing", a truth; let's face it, in the social sciences, there are very few truths, only some trends, and very little from which one can make valid predictions about people with any worthwhile degree of reliability. (An otherwise totally irrelevant aside to illustrate this gap: one of the most insanely cool things I know of from "hard" science is that GPS uses both special and general relativity to make corrections to its timing, and those corrections go in opposite directions.) We elevate the people who make these "amazing discoveries" to superstar status. They get to fly business class to conferences and charge substantial fees to deliver a keynote speech in which they present their probably unreplicable findings.  They go on national TV and tell us how their massive effect sizes mean that we can change the world for $29.99.

Thus, we have a system that is almost perfectly set up to reward people who tell the world what it wants to hear.  Given those circumstances, perhaps the surprising thing is that we don't find out about more fraud.  We can't tell with any objectivity how much cheating goes on, but judging by what people are prepared to report about their own and (especially) their colleagues' behaviour, what gets discovered is probably only the tip of a very large and dense iceberg. It turns out that there are an awful lot of very hungry dogs eating a lot of homework.

I'm not going to claim that I have a solution, because I haven't done any research on this (another amusing point about reactions to the LaCour case is how little they have been based on data and how much they have depended on visceral reactions; much of this post also falls into that category, of course).  But I have two ideas.  First, we should work towards 100% publication of datasets, along with the article, first time, every time.  No excuses, and no need to ask the original authors for permission, either to look at the data or to do anything else with them; as the originators of the data, you'll get an acknowledgement in my subsequent article, and that's all.  Second, reviewers and editors should exercise extreme caution when presented with large effect sizes for social or personal phenomena that have not already been predicted by Shakespeare or Plato.  As far as most social science research is concerned, those guys already have the important things pretty well covered.


(Updated 2015-05-22 to incorporate the details of LaCour's CV updates.)

09 May 2015

Real-time emotion tracking by webcam

The European Commission is giving financial backing to a company that claims its technology can read your emotional state by just having you look into a webcam.  There is some sceptical reporting of this story here.

Highlights:
"Realeyes is a London based start-up company that tracks people's facial reactions through webcams and smartphones in order to analyse their emotions. ...
Realeyes has just received a 3,6 million euro funding from the European Commission to further develop emotion measurement technology. ...

The technology is based on six basic emotional states that, according to the research of Dr Paul Ekman, a research psychologist, are universal across cultures, ages and geographic locations. The automated facial coding platform records and then analyses these universal emotions: happiness, surprise, fear, sadness, disgust and confusion. ...
 [T]his technological development could be a very powerful tool not only for advertising agencies, but as well for improving classroom learning, increasing drivers’ safety, or to be used as a type of lie detector test by the police."

Of course, this is utterly stupid.  For one thing, it treats emotions as if they are real tangible things that everyone agrees upon, whereas emotions research is a messy field full of competing theories and models.  I don't know what Ekman's research says, or what predictions it makes, but if it really suggests that one can reduce everything about what a person is feeling at any given moment to one of six (or nine, or twelve) choices on a scale, then I don't think I live in that world (and I certainly don't want to). For another, without some form of baseline record of a person's face, it's going to be close to impossible to tell what distortions are being heaped on top of that by emotions.  Think of people you know whose "neutral" expression is basically a smile, and others who walk round with a permanent scowl on their faces.

Now, I don't really care much if this kind of thing is sold to gullible "brand-led" companies who are told that it will help them sell more upmarket branded crap to people.  If those companies want to waste their marketing and advertising dollars, they're welcome.  (After all, many of them are currently spraying those same dollars more or less uselessly in advertising on Twitter and Facebook.)  But I do care when public money is involved, or public policy is likely to be influenced.

Actually, it seems to me that the major problem here is not, as some seem to think, the "big brother" implications of technology actually telling purveyors of high-end perfumes or watches, or the authorities, how we're really feeling, although of course that would be intensely problematic in its own right.  A far bigger problem is how to deal with all of the false positives, because this stuff just won't work - whatever "work" might even mean in this context.  At least if a "traditional" (i.e., post-2011 or so) camera wrongly claims to have located you in a given place at a given time, it's plausible that you might be able to produce an alibi (for example, another facial recognition camera placing you in another city at exactly the same time, ha ha).  But when an "Emocam" says that you're looking fearful as you, say, enter the airport terminal, and therefore you must be planning to blow yourself up, there is literally nothing you can do to prove the contrary.  Dr. Ekman's "perfect" research, combined with XYZ defence contractor's "infallible" software, has spoken.
  • You are fearful.  What are you about to do?  Maybe we'd better shoot you before you deploy that suicide vest.
  • The computer says you are disgusted.  I am a member of a different ethnic group.  Are you disgusted at me?  Are you some kind of racist?
  • Welcome to this job interview.  Hmm, the computer says you are confused.  We don't want confused people working for us.
So now we're all going to have to learn another new skill: faking our emotions so as to fool the computer.  Not because we want to be deceptive, but because it will be messing with our lives on the basis of mistakes that, almost by definition, nobody is capable of correcting.  ("Well, Mr. Brown, you may be feeling happy now, but seventeen minutes ago, you were definitely surprised. We've had this computer here for three years now, and I've never seen it make a wrong judgement.")  I suspect that this is going to be possible although moderately difficult, which will just give an advantage to the truly determined (such as the kind of people that the police might be hoping to catch with their new "type of lie detector").

In a previous life, but still on this blog, I was a "computer guy".  In a blog post from that previous life, I recommended the remarkable book, "Digital Woes: Why We Should Not Depend on Software" by Lauren Ruth Wiener.  Everything that is wrong with this "emotion tracking" project is covered in that book, despite its publication date of 1993 and the fact that, as far as I have been able to determine, the word "Internet" doesn't appear anywhere in it.  I strongly recommend it to anyone who is concerned about the degree to which not only politicians, but also other decision-makers including those in private-sector organisations, so readily fall prey to the "Shiny infallible machine" narrative of the peddlers of imperfect technology.

01 May 2015

Violence against women: Another correlate of national happiness?



Introductory disclaimer: This blog post is intended to be about the selective interpretation of statistics. Many of the figures under discussion are about reported rates of violence against women, and any criticisms or suggestions regarding research in this field are solely in reference to research methods. Nothing in this commentary is in any way doubting the very real experiences of women facing violence and abuse, nor placing responsibility for the correct reporting of abuse on the women experiencing it. Violence against women and girls (VAWG) is an extremely serious issue, which is exactly why it deserves the most robust research methods in order to bring it to light.

Back in February 2014, I wrote a post in which I noted the seemingly high correlation between “national happiness” ratings for certain countries and per-capita consumption of antidepressants in those countries. Now I’ve found what I think is an even better example of the limitations of ranking countries based on some simplified metric. I’ve asked my friend Clare Elcombe Webber, a commissioner for VAWG services, to help me here. So from this point on, we’re writing in the plural...

A few months ago, this tweet from Joe Hancock (@jahoseph) appeared in Nick’s feed. It shows, for 28 EU countries, the percentage of women who report having been a victim of (sexual or other) violence since the age of 15. Guess which country tops this list? Yep, Denmark. Followed by Finland, Sweden, and the Netherlands. Remember them? The countries that are up there in the top 5 or 10 of almost every happiness survey ever performed? Down near the bottom: miserable old Portugal, ranked #22 out of 23 in happiness in the post linked to above. (The various lists of countries don’t match exactly between this blog post and the one linked to above because there are different membership criteria, with some reports coming from the OECD, EU, or UN. Portugal was kept off the bottom of the happiness list in the post about antidepressants by South Korea.)

This warranted some more investigating, along the lines of Nick’s previous exploration of the link between happiness and antidepressants. The original survey data page is here; click on “EU map” and use the dropdown list to choose the numbers you want. Joe’s tweet is based on the first drop-down option, “Physical and/or sexual violence by a partner or a non-partner since the age of 15”. While performing the tests that we describe later in this post, we also tried the next option, “Physical and/or sexual violence by a partner [i.e., not a non-partner] since the age of 15”, but this didn’t greatly change the results. In what follows, unless otherwise stated, we have used the numbers for VAWG perpetrated by both partners and non-partners.

First, Nick took his existing dataset with 23 countries for which the OECD supplied the antidepressant consumption numbers, and stripped it down to those 17 which are also EU members. Then, he ran the same Spearman correlations as before, looking for the correlations between UN World Happiness Index ranking and: /a/ antidepressant consumption (Nick did this last time, but the numbers will be slightly different with this new subset of 17 countries); /b/ violence reported by women. Here are the results, which are first sight are rather disturbing:
  • Antidepressant consumption correlated (Spearman’s rho) .572 (p = .016) with national happiness.
  • Violence against women correlated (Spearman’s rho) .831 (p < .0001) with national happiness.
Let’s repeat that: Among the 17 largest economies within the EU, the degree of violence since age 15 reported by women is very strongly correlated with national happiness survey outcomes. When things turn out to be correlated at .831, you generally start looking for reasons why you aren’t in fact measuring the same thing twice without knowing it.

Trying to look for some way of mitigating these figures, Nick tried another approach, this time with parametric statistics. He took the percentage of women reporting being the victims of violence in all 28 EU countries, and compared it with the points score (out of 10) from the UN Happiness Survey. Here is the least pessimistic result obtained from the various combinations:
  • Across all 28 EU countries, violence against women correlated (Pearson’s r) .497 (p=.007) with national happiness.
This is still not very good news. If you’re hoping to show that two phenomena in the social sciences are correlated, and you find a correlation of .497, you’re generally pretty pleased.

Of course, correlation is not the same as causation. Probably nobody would suggest that higher levels of violence against women makes for a happier society, or that higher levels of general societal happiness cause people to become more violent towards women.

So what is going on here? Maybe the methods are seriously flawed. We might have difficulty imagining why Austrian women would report rates of interpersonal violence barely half those experienced by Luxembourgers, or that Scandinavians are assaulting women at over twice the rate of Poles, or that the domestic violence problem in the UK is 70% worse than in next-door Ireland.

But perhaps there are some other factors that might help to explain these numbers. Remember, these are answers being given to an interviewer from the EU Fundamental Rights Agency (FRA); they are not extracted from, say, police databases of complaints filed. Thus, while we can perhaps assume that the reports ought not to be affected too much by the perceived level of danger or social shame involved in revealing one’s situation to the authorities (it’s easy to imagine that that people in countries with high levels of equality and openness—Denmark, say—might feel more able to file charges about violence than in some other countries that are perceived as being more “macho”), the degree to which these data reflect reality will depend to a large extend on people’s degree of willingness to admit being a victim to a stranger. While one would hope that the FRA had thought about that and done the maximum in terms of study and questionnaire design, training of interviewers, etc., to allow women to be frank about their experiences, this isn’t something we were able to find definitively in their reported methodology (available here).

There are huge issues, which have dogged this type of research for many decades, when it comes to asking women to disclose their experiences of abuse. The conventional wisdom amongst researchers and service providers is that victims of abuse are extremely unlikely to reveal their experiences to anyone, and short of the FRA interviewers spending months building rapport with each respondent (which, obviously, they did not do) there is little to be done to mitigate this. Here are just some possible reasons why experiences of abuse might not have been disclosed to researchers, and how this could impact on the results:

·      The sampling method involved visiting randomly selected addresses. A common tactic used by abusive partners is to isolate their victim, primarily as a way of stopping any disclosure or attempt to seek support; so it is not unlikely that women currently in abusive relationships were “not allowed” to take part in the research at all. (If we wish to make great leaps of logic here, we could theorise that this could lead to a higher apparent incidence of VAWG in countries with better support services, as women in those countries were more likely to have been able to leave an abusive situation, and therefore were more able to take part in the research. But we don’t have data for that…)

·      Many women do not identify their experiences as violent or abusive, even when most external observers would say that they plainly are. This may be a defence mechanism, allowing them to avoid having to face up to the truth about their partner, the fragility of their personal safety, or the frightening nature of the world. Admitting that they are the victims of violence or abuse would also imply that they may have to act to change their situation. Therefore, respondents could simply be lying; and, even if a measure of social desirability might be able to detect this (possibly a tall order for such a serious subject), it’s unlikely that the interviewer would administer such a measure. Alternatively, the degree to which women deny that their experiences are violent or abusive might have a substantial cultural component; perhaps women in more “traditional” countries are more likely to justify some behaviours towards them as “normal”.

·      It is not clear, from the methodological background of the report, how issues of confidentiality were explained to respondents. We can reasonably conjecture that if a respondent disclosed that they were currently at serious risk from someone, that the interviewer would have been ethically obliged to do something additional with this information. Many abusers make threats of violence or serious reprisals should their victim make a disclosure (something borne out by the fact that the majority of serious injuries or murders of women by men they know occur at or shortly after the point of separation or disclosure of the abuse to a third party), and this would significantly impact whether or not a woman would answer these questions truthfully. In addition, perceived fear of the authorities may discourage a woman from disclosing; in many countries, the police and social workers often do not have a glowing reputation for providing support, and women may feel that involving them would exacerbate their problems, rather than help to resolve them.

·      Finally, victims who have disclosed their abuse often talk of their feelings of guilt, or that they are to blame for abuse. This shame could be an additional barrier to giving a truthful answer.

We can make some—admittedly sweeping—inferences from the fact that the data do not tell us what we would intuitively expect. We could speculate that those countries we might expect to be more socially “advanced” in terms of attitudes to violence against women could have higher rates of disclosures of abuse in this research because women in those countries feel more able to recognise and name their experiences, or feel more confidence in the authorities being supportive, or have greater trust in the confidentiality of the survey; and therefore are more prepared to report having been the victims of violence. A further conjecture could be that in these countries, women are socially “trained” that these experiences are neither normal nor acceptable, and that victims of violence are entitled to be heard, without being stigmatised. (However, a skeptic might respond that, while these assumptions enable us to put a positive spin on this slightly unusual dataset, they are still only assumptions for which we have little evidence, and do little to address the initial observation, namely that the countries in the EU deemed to be happiest also reported the highest levels of violence against women.) We could add all sorts of social variables into the mix here: availability of relationship education, social stigma towards single mothers, the perception of the state as supportive (or not), and so on. Violence against women and girls is a melting pot of individual, social, and cultural variants, and to date researchers have not been able to neatly set out what it is which makes some men decide to be abusive towards women, nor what makes some communities turn a blind eye to such abuse or even place the blame on the women being abused. Respondents potentially have many more reasons to conceal their experiences of violence and abuse than they might in other research areas, and there is no straightforward way of controlling for these. (Psychologists have devised various ways of controlling for social desirability biases, but it is not clear to us that these take sufficient account of cross-cultural factors; see Saunders, 1991.)

However, let’s assume for a moment that it might be valid to take the numbers in the report as not being directly reflective of the underlying problem, but instead as presenting a combination of the actual prevalence, multiplied by a “willingness to acknowledge” factor. At a certain point, this could mean that you could see higher numbers in the survey for countries where there’s actually less of a problem. For example, let’s say that the true rate of violence against women in Denmark is 60%, and that 87% of Danish women are prepared to discuss their experiences of violence openly; multiply those together, and there’s the 52% reported rate from the EU survey. Meanwhile, perhaps the true rate in Poland is 76% (note: we have no evidence for this; we are choosing Poland here only because it is the country at the bottom end of the FRA’s list), but only 25% of Polish women are prepared to discuss it; again, multiply those numbers together and you get the reported rate of 19%. In fact, this line of reasoning is commonly used by people working on the front line of VAWG support. For example, in one London borough, reports to the police of domestic abuse in 2014 were over 40% higher than in 2013, and this is considered to be a good thing; it’s assumed that the majority of domestic abuse goes unreported, and thus additional reports are just that: additional reports, rather than additional instances. But without more data from other sources and approaches, we just don’t (and can’t) know.

Here’s the kicker, though: if you choose to take the line that these figures “can’t possibly be right”, and that in fact they may even show the opposite of the real problem, that raises the question of why it’s OK to look for an alternative explanation for the figures on violence (or other social issues, such as, perhaps, antidepressant usage), but not for those on other phenomena, such as (self-reported) happiness. What gives data on happiness the kind of objective quality that legitimises all the column inches, TV airtime of happiness gurus, and government policy initiatives to try and boost their country’s rank from 18 to 10 in the UN World Happiness Index, if you’re simultaneously prepared to try to look very hard for reasons to explain away numbers that appear to show that your favourite “happy” country is a hotbed of violence against women?

And, even more importantly: whatever your position, do you have evidence for it?

You can find the dataset for this post here. (Yes, the filename does give away how long we have been working on this post!) It also includes all the data you need to re-examine the post about antidepressants from February 2014.

References
Saunders, D. (1991). Procedures for adjusting self-reports of violence for social desirability bias. Journal of Interpersonal Violence, 3, 336–344. https://doi.org/10.1177/088626091006003006 (Full text available here.)

29 March 2015

Open Access journals: what's not to like? This, maybe...

When I used to work in an office, my boss used to say that any time he had a good idea, he could come to me and in ten minutes he'd know everything that might go wrong with it.  He often went ahead anyway, and his ideas often worked, but at least he was forewarned.  So in that spirit, here goes.

I'm a little concerned by all the hype around Open Access (OA) journals.

Yes, I know that traditional journal publishers are evil, and make more money and higher gross margins and have bigger car parking spaces than Apple, and I agree that when taxpayers fund research then taxpayers should have access to it.  However, I'm not sure that just because all of the above may be true, that our current model of OA journals is necessarily the solution.  I have a number of concerns of what may happen as the OA model takes hold and, as everybody tells me is going to happen, becomes dominant.  This post is intended to start a discussion on those concerns, if anyone's interested.

1. It's the economy, stupid

One of the strengths of the traditional publishing model is that, to a first approximation and allowing for all kinds of special circumstances, the editor-in-chief of a half-decent journal doesn't have to worry about filling it.  Indeed, many journals proudly promote their rejection rate on their home page, next to their average turnaround time.  "We reject 90% of submissions; don't waste our time unless you've got a good story to tell", is the message (with, of course, all of the predictable effects on publication bias that this implies).  Doubtless the editor-in-chief has some financial targets to meet, perhaps in terms of not blowing the production budget on full-page colour pictures of kittens, but this is not a job whose holder is principally tasked with revenue generation.  The money is coming in pretty steadily from sales of packages of journals to institutions around the world (even if some of these institutions are starting to take exception).  The editor gets to concentrate on, among other things, maintaining the journal's impact factor --- hopefully using methods that are a little less blatant than this.

With OA journals, funded principally by article processing charges paid by authors, things are likely to be a little different.  No matter how dedicated to academic integrity and the highest possible scientific standards the editorial staff want to be, money is right there in the equation every day, especially for an online journal with almost no physical limits to its size.  How many articles can we get through the review process this month?  Can we upsell the author to the full-colour package?  Why do so many people want hardship waivers?  (Oh, and I have yet to see any suggestion that OA journals will be less concerned about their impact factor than traditional journals.)

The idea, of course, is that authors will not be reaching into their own pockets to pay the article processing charges.  The intention is that the fee of $1,000 or so to publish the results should be budgeted for out of the project's funding.  After all, it's only a waffer-thin thousand bucks, the kind of money some projects probably have slopping around at the end anyway if the participants didn't eat all of the M&Ms.  But once funding agencies catch on, will they allow grant proposals to include specific line items for OA publishing, when publication in one of the high-prestige traditional journals --- which you promised them, earlier in the proposal, were definitely going to be interested in your groundbreaking project --- is free?  And what about the independent researcher with no budget, who may have something interesting to say, but no money?  Should such a person have to fund publication from their own pocket?

I'm afraid that the money always, always finds a way to affect things.  Someone, somewhere in the process, will be directly incentivised to increase revenue.  (In France, where I live, gambling is a state monopoly, which means that whatever arms-length construction they have put together, somewhere there is someone who essentially works for the government and yet has a performance target to sell more scratchcards to the urban poor, even though gambling is officially a social problem.)  How does this affect you as the editor-in-chief of an OA journal?  Maybe you ask your action editors to tell reviewers to be less picky about certain things.  Maybe you suggest to an author that splitting these results into two articles will be to everyone's advantage - after all, the publication fee is coming out of the grant money, and as it stands it is a pretty long paper manuscript for someone to have to wade through at one sitting...

The corollary of this is that the PI presenting an article for publication is a paying customer.  Now when I go to make a $1,000 purchase, I'm generally greeted with open arms.  I certainly don't expect to have to pass quality control checks before I'm allowed to spend my $1,000.  The psychology of the OA model is going to be interesting indeed.  (Compare what happened in the UK when public universities started to charge tuition fees; all of a sudden, the idea of a student being given a failing grade became, for many people, a consumer protection issue.  "I paid to come here and get a degree, how dare you tell me I can't have one?", ran the argument.  Too many unhappy punters, and the Vice-Chancellor is touring the stricter departments to ask them to be a little more, um, flexible in their marking criteria.)

I found a pertinent example shortly before putting this post (which has taken a while to draft) online.  Here is a note from Nandita Quaderi, who is "Publishing Director, Open Research" at Scientific Reports, which is part of Nature Publishing Group.  Nandita is pleased to announce that henceforth, "a selection of authors submitting a biology manuscript to Scientific Reports will be able to opt-in to a fast-track peer-review service".  Needless to say, this service comes "at an additional cost", being provided by a for-profit organisation called Research Square.   (An editor of Scientific Reports has resigned over this.)  So now, I'm paying to publish, and I'm paying to have my article reviewed.  What could possibly go wrong with the objectivity and rigour of the scientific process?

2. Access is not the biggest problem science faces right now

Another issue is that most OA journals do not address the ongoing problems of the peer review system.  I would argue that currently, failures of peer review are a bigger threat to science than paywalls.  If reviewers are allowing bad science through --- or erroneously recommending rejection of good articles --- then getting free access to the resulting error-filled literature is the least of our problems; and I have yet to see a coherent argument why the OA review process might be inherently any more rigorous than that at traditional journals.

Some online journals, such as The Winnower, have adopted a radical solution to this: anyone can publish an article, without any prior review process, with the idea that people will come along and review it afterwards.  This seems attractive at first sight, except that people typically have even less incentive to act as a reviewer once the article is "out there", even if it doesn't yet have the status of a citable article with a DOI (a status which, incidentally, the article's own author decides to award it, at a time of his or her own choosing).

It seems to me that OA journals are to some extent hitching a ride on the back of the traditional journals, which have created (and still sustain) the fundamental mode of operation that we know and love/hate: author sends in MS, editor checks it, editor selects reviewers, reviewers approve or request changes, editor finally accepts or rejects.  This system more or less works --- give or take the criticisms of peer review as "broken", which have a lot of merit but which, as I noted above, it seems to me that OA (in and of itself) doesn't do much to address --- because people generally have confidence in it.  Not necessarily absolute confidence, but we know how it's meant to work and how to spot when it isn't working.  We (like to) believe that the editors do not generally accept (too many) articles from themselves and their buddies (or at least, that they risk getting called out for it if they do), that they select reviewers who are competent in the relevant subfields, that the reviewers do an honest and unbiased job, etc.  (Of course, the reviewer who is doing "excellent quality control" with *your* article is an incompetent idiot who has failed to understand even the most basic concepts of *my* article, but that's part of the game.)

So, when something like Collabra, the new OA mega-journal from the University of California, launches, they can put pictures of respected people on the front page where they introduce their editorial board, thus sending a message that the review process will be every bit as rigorous as it is for a traditional journal.  Readers are reassured, and authors know they will need to submit work of a high standard.  But to me this only works because the majority of people who are being held up as examples of the quality of the journal have good reputations, which have been made within the traditional process.  How does this scale?  What does the publication process look like in 10 or 20 years time, if the traditional journals have mostly gone and we make our reputations with OA (web-)publishing, blogs, and social media presence?  (Yes, impact factor is broken. But where is the dominant, credible alternative that everyone will be prepared to switch to?)

This doesn't mean that Collabra will be full of articles promoting homeopathy after a few months.  But over time, the relationship between authors, reviewers, and journals will change, in ways that we can't necessarily predict.  That doesn't mean the sky will fall, but it does mean that there will be perverse situations that may or may not be worse than what we have to put up with now.

3. Ham, spam, and all points in between

I also worry that the line between "legitimate" and "spam" OA journals will start to blur.  Currently we can all point and laugh at the semi-literate invitations to publish in (or join the Editorial Board of) those pseudo-journals with plausible-sounding names, strange salutation styles in their e-mails, and an editorial address in a Regus suite in San Antonio, from which manuscripts are presumably forwarded to the journal's real staff in Cairo or Mumbai.  But these fraudulent (whatever that means...) journals will improve, and it will become hard to tell the "fake" from the "real".
A few weeks ago, I was asked to review an article by an OA journal that was part of a London-based publishing outfit.  I genuinely couldn't decide if they were spammers or genuine: the journals mentioned on their web site all seem to exist, and about a third of them are indexed in PubMed.  How good or bad is that?  I recommended rejection, as the article would have been of little interest to the readers of the journal, according to its own profile.  I wonder what the lead author did next (assuming that my recommendation to reject was the editor's verdict as well)?  Did he appeal, as a "paying customer", to the editor in chief?  Or did he maybe send the article to another OA journal, on the basis that he will eventually find somebody, somewhere, who wants $1,000? (*)

I think, though, that perhaps the bigger risk in the meeting of "legitimate" and "spam" journals is through the trimming of standards at the "legitimate" end. Look at what happened when the Saudis decided to throw some money at education, and suddenly King Abdulaziz University is ranked #7 in the world in mathematics.  Uh-huh.  Sure.  So what happens when that university, or others with rather more money to burn than academic integrity, starts its own OA mega-journal?  Exactly what will be the conditions of scientific neutrality under which the editor-in-chief reviews articles by, say, the children of minor members of the Saudi ruling family?  Perhaps someone will create an authoritative clearing house to administer a sliding scale of which journals are "real" versus "spam".  But who would run such an organisation?  The AAAS?  ISO?  Standard & Poor's?  Google?  And who would ultimately be responsible for the "legit"/"spam" decisions?

Historically, publisher-led journals seem to have been mostly spam-free; it would be interesting to establish why this was. High barrier to entry in the world of ink and paper?  Old-fashioned academic and intellectual integrity, despite the profits?  Risk of reputational damage if, say, Springer (cough) or Sage (cough) were to acquire a reputation for publishing garbage?  I don't know what the reasons are, but it created the current situation whereby --- whatever the other problems in the system --- a journal that exists in a print edition is generally regarded, at least by default, as having some degree of seriousness.  I worry that we will end up in a situation where we don't have a simple way to tell whether we can take a "journal" (in the widest possible sense) seriously or not.  In such situations, humans tend to apply some simple heuristics, which scammers have many centuries worth of experience exploiting.

4. A modest (and, as yet, barely sketched out) proposal

Do I have an alternative?  Well, when my boss came to me with his ideas, I usually didn't, but in this case I do have a tentative suggestion.  What if the funding agencies ran a few journals?  After all, these are (generally) the representatives of the taxpayers, who --- as the Open Access movement is right to point out --- pay for the research and ought to have free access to the results.  Yet currently, they rely on "the system" to work, and for researchers to muddle their way through that system.  In the traditional model, the readers pay, and in theOA model, the authors pay.  Both systems have their deficiencies.  Supposing we had a parallel model where nobody paid (except a general fund, set up to guarantee neutrality)?

Those of a libertarian bent might argue that the government shouldn't be involved in academic publishing, but the stable door closed on that when we started to take their money to do the research.  Some might also argue that an funding agency-sponsored journal might be highly politicised, but then, /a/ why should it be more politicised than the handing out of the money, /b/ the Rind/Lilienfeld saga showed that politicians can pressure "independent" journal publishers into submission too, and /c/ there will always be other outlets; I'm just modestly proposing a "third way".  (As a bonus, this would seem to be a good fit with the aims of the pre-registration movement.)



Notes:

1. I'm aware that this is a rather long and at times rambling post.  It started life in a frenzied evening of writing just after I got out of hospital after a stay that lasted the better part of three weeks, and that still shows.  I should probably have scrapped it and started again, or at least sat down and rearranged the paragraphs, but I wanted to get the ideas out there within a reasonable time frame.  I hope some of them are useful.

2. I want to thank Rolf Zwaan for some helpful discussions on an earlier draft of this post.  Rolf disagreed with much of what I had written, and I've only made a few changes, so he probably still disagrees with a lot of it.  I should point out that my use of the example of Collabra (for whom Rolf is an editor) above is not based on any specific criticism of that journal, but merely as a salient example; Rolf's tweet about his appointment as an editor at Collabra was the spark for my writing of this post.

(*) Update 2016-11-28: I was re-reading this post because reasons, and I noticed this dangling question.  I googled the title of the article... sure enough, it was accepted, despite my recommendation to reject.

28 August 2014

Why we believe our article "A critical reanalysis of the relationship between genomics and well-being" is correct

Earlier this week (Monday 25 August 2014), our article was published in PNAS:
Brown, MacDonald, Samanta, Friedman, and Coyne (2014). A critical reanalysis of the relationship between genomics and well-being. doi:10.1073/pnas.1407057111

This was a critique of:
Fredrickson, Grewen, Coffey, Algoe, Firestine, Arevalo, Ma, and Cole (2013).  A functional genomic perspective on human well-being.  doi:10.1073/pnas.1305419110

There has been some discussion of our article on social media.  In particular, some people have noted that the principal authors of the original article (Cole and Fredrickson) have replied with a 550-word letter (which I guess is all they were allowed; they have more material, as shown below) claiming that our article contains multiple errors and is, hence, invalid.  So I'm writing this blog post to put our side of the story and explain why we feel that our article is correct, and that Cole and Fredrickson have not made a dent in it.  I was a little disappointed that Dr. Martin Seligman, on the APA Friends-of-PP mailing list, chose to describe our article as a "hatchet job". We believe that we have identified a number of serious scientific problems with Fredrickson et al.'s original article, which are not adequately addressed either by Cole and Fredrickson's published letter, or by their more extensive unpublished analysis.

First, some references, to save me linking to them repeatedly below.

Fredrickson et al.'s original article
Fredrickson et al.'s original supporting information (SI)
Coyne's letter to PNAS, criticising Fredrickson et al.'s factor structure
Cole and Fredrickson's letter to PNAS, replying to Coyne
Our article (in final draft form; I'm not sure if I'm allowed to link to the PDF of the published article in full PNAS format.  Any differences will be cosmetic, e.g. numbering of references.)
Our supporting information (SI) - download the PDF file marked "Appendix"
Cole and Fredrickson's letter to PNAS, claiming our analysis has many errors
Cole and Fredrickson's additional analysis for their claim that our analysis has many errors
Neuroskeptic's blog post, which provides additional evidence for the deficiencies in Fredrickson et al.'s regression procedure.
Dale Barr's blog post, which approaches the regression issues in a different way, but also finds many problems and provides graphical demonstrations of how unlikely Fredrickson et al.'s results are.

I will address each of the principal points of Cole and Fredrickson's response to our article in turn (although not in the exact sequence in which they appeared in their letter). Before I begin, though, I want to apologise for the length and complex nature of some of the points I will be making here (which is unfortunately necessary, as most of the issues under discussion here are quite technical).  This is particularly true of the section entitled "Bitmapping?" below, which might appear, to the reader who has tried to struggle through our article and SI, and Cole and Fredrickson's letter and additional analysis, to be not much more than a case of "he said/she said".  I note, however, that each of the major issues that we raised in our article is sufficient, on its own, to render Fredrickson et al.'s results meaningless.  These major issues are:
- The MHC-SF psychometric scale does not measure hedonic versus eudaimonic well-being
- Fredrickson et al.'s regression procedure produces mostly spurious correlations, even with random psychometric data
- The errors in Fredrickson et al.'s dataset directly invalidate their published numerical results

MHC-SF factor analysis

Cole and Fredrickson criticise us for attempting to perform factor analyses on the MHC-SF psychometric with such a small sample size. It is interesting to contrast this with Cole and Fredrickson's 2013 letter to PNAS, in reply to Coyne's criticism of the high degree of intercorrelation between their "hedonic" and "eudaimonic" factors, in which they describe how they themselves performed exploratory and confirmatory factor analyses on exactly the same data, apparently claiming to have found the hedonic/eudaimonic factor pair with a very good model fit. (A p-value of < .0001 is offered, but without sufficient context to establish to what exactly it refers; however, the message seems clear: we did EFA and CFA and obtained a fantastic model.)  We attempted to reproduce this, but were unable to do so; indeed, we noted ourselves in our article that the sample size was an issue here.  But the only reason we were doing this was in an attempt to replace the factor analyses that Cole and Fredrickson claimed, in their 2013 letter, to have performed.  We look forward to seeing the results of those analyses, which have so far not been published.

Still on the factor analysis, Cole and Fredrickson claim that their assumption of a hedonic/eudaimonic split for the MHC-SF scale is supported by three references from Fredrickson et al.'s article. We have examined these references (for your convenience, they are here, here, and here) and have not found any point at which any of them supports this claim, or indeed makes any statements at all about the factor structure of the MHC-SF.  Please feel free to check this yourself, and if you find such a discussion, let me know the page number.  In the meantime, the claim of a two-factor, hedonic/eudaimonic split for the MHC-SF seems to be supported by no published evidence.  (However, there has been plenty of reporting in the literature of a clear three-factor structure, e.g. here and here and here.)

Again, we stand by our analysis: Fredrickson et al.'s claim for a hedonic/eudaimonic factor split of the MHC-SF is not supported by theory, nor by the data, nor by historical studies. The factor structure of the MHC-SF that emerges from Fredrickson et al.'s dataset is unclear, but of the possible two-factor structures, the one that we described in our article and SI (i.e., "personal well-being" and "evaluative perception of the social environment") is a considerably better fit to the data in all respects than Fredrickson et al.'s claimed hedonic/eudaimonic split. The only structure that has been documented for the MHC-SF in prior published work is a three-factor structure corresponding to its three subscales, as designed by Keyes.

Bitmapping?

The "bitmapping" operation to which Cole and Fredrickson devote part of their letter (and most of their additional analysis document) is merely an artifact of the way in which our R program loops over all possible combinations of the 14 MHC-SF psychometric items into two factors. There are many ways in which we could have done this that do not involve the programming technique of converting an integer into a bitmap. Indeed, the inclusion in our SI document of the brief mention of how our outer loop works (the inner loop does the regressions, using Fredrickson et al.'s exact parameters) is arguably slightly redundant, but we included it to facilitate the understanding of our code, should someone wish to undertake a reproduction of our results.

Cole and Fredrickson's analysis seems mainly aimed at demonstrating that our "bitmapping" technique is an inadequate way to resample from a dataset. We agree. We never suggested that it was a way to perform resampling. We are not even sure how it could. We are not performing any resampling, bootstrapping, or any other form of Type 1 error reduction. Our program simply generates every possible factor combination of the psychometric data and determines whether or not it appears to show an effect, using Fredrickson et al.'s own regression procedure. The results of this procedure demonstrates that, no matter how the data are sliced or diced, Fredrickson et al.'s regression procedure will generate apparently statistically significant results in the majority of cases; indeed, in most of those cases, it will appear to show effect sizes larger than those found by Fredrickson et al.

The graphs in our SI document (Figures 7-11) plot the results obtained by iterating over all possible two-factor combinations of several forms of psychometric data: Fredrickson et al.'s actual data, assorted random numbers, etc.  We are not completely sure what Cole and Fredrickson think that these graphs show.  To be clear: they show all the possible "effects" (relationships between psychometric "factors" and gene expression values) results that Fredrickson et al. could have obtained, had they chosen another factor split of their data from the MHC-SF scale than the one that they did choose.  Figure 7, in particular, uses the real psychometric data to show that most of the possible factor combinations would have produced effects greater in magnitude than the ones that Fredrickson et al. claimed to show that their "Hedonic/Eudaimonic" split were associated (presumably uniquely) with differential gene expression.

Why, then, does this procedure continue to produce apparently significant results even when the psychometric data are replaced with uniformly-distributed random numbers (aka "white noise")?  We believe that this is due to strong correlations within the gene data.  As shown by Neuroskeptic, this leads to an enormous false-positive rate.  Thus, when Fredrickson et al. ran their regression procedure (which we called "RR53") and averaged the resulting correlation coefficients, they were making the elementary mistake of running a t-test on a set of non-independent observations.

Incidentally, there is an alternative way of doing the regression analysis.  Fredrickson et al. regressed each individual gene on Hed/Eud (and some control variables), collected the 53 coefficients per IV, and averaged them; this is what we called the "RR53" procedure.  The alternative is to average the gene expression values and regress this average on Hed/Eud.  We had noticed that this gave non-significant results. Then, just after the PNAS window for updating our supplementary information document closed, a colleague --- who, I believe, wishes to remain anonymous --- pointed out that using this alternate method, the apparent effect sizes are exactly the same as the ones "found" by RR53.  Only the p-values are different.  We believe this is because, when the RR53 procedure picks up the regression coefficients of the individual genes to analyse them, it conveniently loses the associated confidence interval (almost all of these coefficients are associated with non-significant t-tests or model ANOVA) and re-inserts them into the mix as if they were perfect fresh data from a measuring instrument, whereas in fact they are almost all carrying an amount of "noise" that makes them highly unreliable.

We have made many of our materials available online, including our program's source code, and we are happy to share our other files (some of which are quite voluminous) on request, or to answer any specific questions that anybody might have about how our program works. (We could have reproduced this work with SPSS, but it would have taken an awfully long time.)

Thus, we stand by our analysis: Fredrickson et al.'s regression procedure is guaranteed to produce huge numbers of spurious "effects" which have no psychological or physiological meaning.

Issues with the dataset

Finally, Cole and Fredrickson claim that they have recently reproduced the same numerical results as their 2013 study with a new sample.  I will leave aside, for now, the question of how meaningful it is to show that a procedure which has been criticised (by us) for producing invalid results can be "shown" to be correct if it produces much the same results a second time; perhaps there is some validity in having two data points rather than one.  However, this question turns out to be irrelevant.  In Cole and Fredrickson's reply, they notably fail to address the question of the various errors in their original dataset, which we discuss quite extensively (and for good reason) in our supporting information. In particular, Cole and Fredrickson do not address the coding error in their original dataset for participant SOBC1-1299, which we examine on pages 3 and 24 of our Supporting Information. Near the end of our Table 7, we show that this coding error can be (and should have been, in the original study) resolved in one of two ways, either of which results in a reduction of over half in the magnitude of the effect for "hedonic" well-being that was reported by Fredrickson et al. (as well as a small change in the magnitude of the effect for eudaimonic well-being). In other words, had this coding error not existed in the 2013 dataset, Fredrickson et al.'s figures of +0.28(hedonic)/-0.28(eudaimonic) for the 2013 study should have been calculated and reported as approximately +0.13(hedonic)/-0.27(eudaimonic). To subsequently obtain +0.25(hedonic)/-0.21(eudaimonic) with the new sample thus appears to be evidence against a successful reproduction of the original results (unless some new theory can explain why the effect of hedonic well-being has suddenly doubled).

Summary

In summary, we stand by our overall conclusions, namely that Fredrickson et al.'s article does not tell us anything about the relationship between different types of well-being and gene expression. We will be sending a summary of the above position to PNAS for peer review and possible publication as a Letter to the Editor.

I am sure that this will not be the final word on this matter. We trust that Cole and Fredrickson will go back and re-examine their study in the light of our response, and perhaps return with some additional information that might clarify matters further. We anticipate that our peers will also contribute to this debate.

Edit history
2014-08-27 22:08 UTC First version.
2014-08-28 11:50 UTC Removed the rather clunky reference to trying to factor analyse the gene data; added link to Neuroskeptic's blog post, and discussion of the problems with the RR53 procedure.
2014-09-15 23:27 UTC Added link to Dale Barr's blog post.
2014-10-16 22:03 UTC Fixed a couple of typos.