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By Barry Leiba | September 29th 2009 12:58 PM | 3 comments | Print | E-mail | Track Comments
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About Barry Leiba

I’m a computer software researcher, and I'm currently working independently on Internet Messaging Technology. I retired at the end of February... Full Bio

In the issue dated 10 October, Science News reports on a study that suggests that peer reviewers prefer positive results:


Peer reviewers for biomedical journals preferentially rate manuscripts with positive health outcomes as better, a new study reports.

Now, at first blush this might seem like a “Duh!” moment, but it’s not. We obviously would like to see positive results when we’re studying a new medicine, but there’s a great deal of value in publishing negative results as well. It tells us what medicines don’t work. It tells researchers what direction to take, exposing some of the blind alleys. It’s critically important information, and that’s true in other fields, as well.

Consider studies of acupuncture, of astrology, and so on. There are a great many people who think those work — certainly enough to warrant a serious look with controlled studies. And controlled studies have been done. They show that astrology doesn’t work at all. They show that acupuncture works as a placebo: “fake” acupuncture is as effective as “real” acupuncture. These are useful results.

Consider herbal remedies: we know that herbs do have active substances in them, but there are lots of claims and we’d like to sort them out. Does Ginkgo biloba help with dementia? Does Echinacea reduce cold infections? Is Valerian effective as a sedative? Does St John’s wort work against depression? Studies say no, no, maybe, and yes, respectively. And the “no” results are arguably just as important as the others.

But it’s not just in medicine that we see a preference for favourable results. It’s true in my field of computer research, as well. In fact, while it would be quite important to see, say, methods of spam filtering that seemed like good ideas but fell flat, we rarely see people submitting them, and I’m quite certain that reviewers would lean toward rejecting them in favour of “more interesting” papers with “better” results.

Probably one significant reason for the lack of submissions is that people aren’t eager to document “failure”. That means that it’s incumbent upon the review and publication system to actively encourage the publication of good ideas that didn’t work out. The “good ideas” part of it is key, of course: there’s plenty of work that went nowhere, but that wasn’t promising to begin with. There’s limited value in publishing that stuff.

On the other side, reviewers should be looking at the value a study has for teaching or for directing future work, and for confirming or overturning common theories. A paper that shows definitively that something we expected to work doesn’t... is arguably more important than one with a partial result in the expected direction.


Comments

kerrjac's picture
Good points all around.

But one consideration relates to the logic of hypothesis-testing, which renders unsupported hypotheses uninterpretable (ie, you can't support the null). Technically studies that failed to find, say, the benefits of acupuncture, did just that; they didn't find that acupuncture is bunk per se. While the latter is one interpretation, giving heed to the alternative (ie, there is a relation, it just wasn't supported) is important as a means of honing research methods. It should push scientists to re-examine the situation and (for lack of a better word) take responsibility for constructing a better study.

In the case of acupuncture, while placebo is always an option, still we see people continuing to use it and to claim benefits from it; researchers who failed to support its benefits might hone their direction in any number of ways, be it their selection criteria (eg, focusing only on people with problems that conventional medicine couldn't solve; breaking results down by ethnicity), outcome measures (eg, making them broader or narrower), or manipulation.

Science is in large part based on observation and quantification; human error always being a given, there are still many common day associations that science finds difficult to quantify (such as fatigue and MS). I'm with you with in placing more of an emphasis on unsupported results, but noting that failure to find a relation may be less of a reflection of the construct rather than of accepted methodology.

barryleiba's picture
Thanks for the comment, and I agree with you.  Part of the job of the peer reviewers, and of the other researchers reading the published study, is to analyze the methodology.  Different studies often give conflicting results, and that's mostly due to methodological differences.

On acupuncture in particular, note that I didn't say that it's bunk, but that controlled studies (specifically, certain recent ones) have shown that "fake" acupuncture works as well as "real".  What the reader takes from that is up to the reader, and, indeed, some researchers reading it might see aspects of the studies' methodology that they can change in a future study.

Pain is a tricky thing to study, because it's so subjective.  If you think something has relieved your pain, then, by definition, it has, whether it be aspirin, acupuncture, or artichoke hearts.  Sleep is similarly difficult: a study from a couple of years ago found that over-the-counter sleep remedies give no more than 10 minutes more sleep a night, on average; studies can quantify that.  And, yet, if you take one and feel more rested in the morning, well, then, it worked for you.

But that's a whole different discussion, perhaps for another post.

Fred Phillips's picture
Communication theory is a better lens for this than hypothesis logic. Claude Shannon said that a message of n bits is highly informative if it is surprising. Conversely, a message of n bits saying that a high-probability event has indeed happened, is not so informative. This should be a criterion for deciding whether to publish studies having negative outcomes.

So (to use the favorite example of another probabilist, Emanuel Parzen), if I send you a paper showing that in recent months there has been no change in the probability of the sun rising each morning, please reject it. But if I report that certain sea temperatures have not varied, this could be a valuable part of the total picture of global climate change, and good input for climate modelers. So you should give serious consideration to publishing it if my methodology is sound.

If we fail to reject a null hypothesis, we have of course not "proved" the null. However, failure to reject can be construed as "support" for the null, within certain bounds, especially if we speak colloquially.  Also, we usually have considerable latitude in the way we express the research question, and so, some latitude in which proposition is written as the null and which as the alternative hypothesis.

But hypothesis is the language of controlled experimentation, and testing holistic treatments like acupuncture by rigidly controlling non-experimental variables obviously destroys the holism of the matter and prejudices the experiment. That's another whole discussion.

Anyway, I put forth "how surprising the result is, whether positive or negative" as an important component of the publication decision.


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