Pre-registration has made medicine less effective
2016-03-01 19:53:22.478094+01 by Dan Lyke 0 comments
PLOS One: Likelihood of Null Effects of Large NHLBI Clinical Trials Has Increased over Time
17 of 30 studies (57%) published prior to 2000 showed a significant benefit of intervention on the primary outcome in comparison to only 2 among the 25 (8%) trials published after 2000 (χ2=12.2,df= 1, p=0.0005). There has been no change in the proportion of trials that compared treatment to placebo versus active comparator. Industry co-sponsorship was unrelated to the probability of reporting a significant benefit. Pre-registration in clinical trials.gov was strongly associated with the trend toward null findings.
Or: When you start asking researchers to pre-register their trials, it becomes way harder to cherry pick only the good results.