[From the blog post, “What Is Preregistration For?” by Neuroskeptic, published at Discover Magazine]

“The paper reports on five studies which all address the same general question. Of these, Study #3 was preregistered and the authors write that it was performed after the other four had been completed. It was also larger than the others. The results of Study #3 closely matched the other studies’.  So far, so good.”

“However, according to Daniël Lakens on Twitter (I’m not sure how he knows this), Study #3 was conducted on the instruction of the editors (during peer review).”

“Now, this is where alarm bells started ringing for me. If Psychological Science asked the authors of this paper to carry out Study #3, the reason, presumably, is that they weren’t fully convinced by the other studies. The journal wanted more evidence for the hypothesis that ‘participants in a dimly lit room or wearing sunglasses tended to estimate a lower risk of catching contagious diseases.’ That’s understandable, but what would the editors have done if the results of Study #3 had come back negative?”

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