PLoS biology Figure 1 dataPrevalence of reporting of randomisation, blinded assessment of outcome, sample size calculation and conflict of interest in 146 publications describing in vivo research identified through random sampling from PubMed;PLoS biology Figure 3 dataReporting of randomisation, blinded assessment of outcome, sample size calculations and conflict of interest reporting and journal impact factor for 2671 publications describing the efficacy of interventions in animal models of eight different diseases identified in the context of systematic reviews,PLoS biology Figure 5 dataReporting of randomisation, blinded assessment of outcome, sample size calculation and of inclusion or exclusion criteria in 1173 publications describing in vivo research published from 5 leading UK institutions (labelled A through E).

The reliability of experimental findings depends on the rigour of experimental design. Here we show limited reporting of measures to reduce the risk of bias in a random sample of life sciences publications, significantly lower reporting of randomisation in work published in journals of high impact, and very limited reporting of measures to reduce the risk of bias in publications from leading United Kingdom institutions. Ascertainment of differences between institutions might serve both as a measure of research quality and as a tool for institutional efforts to improve research quality.