Wednesday, June 5, 2013

The Value of Pre-Registration - comments on a letter in the Guardian

The Guardian just published a great letter, signed by many of the leaders of our field, calling for pre-registration as a way to improve our science. I imagine they would have had many more signatories if the authors had put out a more public call. I'll add my virtual signature here. If you agree with the letter, please make sure your colleagues see it and add your virtual signature as well.

I think pre-registration is the way forward. I hadn't pre-registered my studies before this past year, but I've started doing that for all of the studies for which I have direct input into the management of the study. I hope more journals will begin to conduct the review process before the data are in, vetting the method and analysis plan and then publishing the results regardless of the outcome. But even if they don't, pre-registration is the one way to demonstrate that the planned analyses weren't p-hacked. My bet is that, as the ratio of pre-registered to not-pre-registered studies in our journals grows, researchers will begin to look askance at studies that were not pre-registered. The incentive to pre-register will increase as a result, and that's a good thing.

Even if journals don't accept studies before data collection, pre-registration helps to certify that the research showed what it claimed to show. And, pre-registration does not preclude exploratory analyses. They can just be flagged as such in the final article, and readers will know to treat this explorations as preliminary and speculative, requiring further verification. I personally favor having two labeled headings in every results section, one for planned analyses and one for exploratory analyses. Even without pre-registration, that's a good approach. But pre-registration certifies the planned ones.

It's easy to pre-register your results and post your data publicly. You can do that with a free account at

update: fixed formatting errors.