LAUSR

OBJECTIVE Pre-specification of statistical methods in clinical trial protocols and Statistical Analysis Plans (SAPs) can help to deter bias from p-hacking, but is only effective if the pre-specified approach is made available. STUDY DESIGN AND SETTING For 100 randomised trials published in 2018 and indexed in PubMed we evaluated how often a pre-specified statistical analysis approach for the trial's primary outcome was publicly available. For each trial with an available pre-specified analysis, we compared this to the trial publication to identify whether there were unexplained discrepancies. RESULTS Only 11 of 100 trials (11%) had a publicly available pre-specified analysis approach for their primary outcome; this document was dated before recruitment began for only one trial. Of the 11 trials with an available pre-specified analysis approach, 10 (91%) had one or more unexplained discrepancies. Only 4/100 trials (4%) stated that the statistician was blinded until the SAP was signed off and only 10/100 (10%) stated the statistician was blinded until the database was locked. CONCLUSION For most published trials, there is insufficient information available to determine whether results may be subject to p-hacking. Where information was available, there were often unexplained discrepancies between the pre-specified and final analysis methods.