Badges for sharing data and code at Biostatistics: an observational study

Background: The reproducibility policy at the journal Biostatistics rewards articles with badges for data and code sharing. This study investigates the effect of badges at increasing reproducible research. Methods: The setting of this observational study is the Biostatistics and Statistics in Medicine (control journal) online research archives. The data consisted of 240 randomly sampled articles from 2006 to 2013 (30 articles per year) per journal. Data analyses included: plotting probability of data and code sharing by article submission date, and Bayesian logistic regression modelling. Results: The probability of data sharing was higher at Biostatistics than the control journal but the probability of code sharing was comparable for both journals. The probability of data sharing increased by 3.9 times (95% credible interval: 1.5 to 8.44 times, p-value probability that sharing increased: 0.998) after badges were introduced at Biostatistics. On an absolute scale, this difference was only a 7.6% increase in data sharing (95% CI: 2 to 15%, p-value: 0.998). Badges did not have an impact on code sharing at the journal (mean increase: 1 time, 95% credible interval: 0.03 to 3.58 times, p-value probability that sharing increased: 0.378). 64% of articles at Biostatistics that provide data/code had broken links, and at Statistics in Medicine, 40%; assuming these links worked only slightly changed the effect of badges on data (mean increase: 6.7%, 95% CI: 0.0% to 17.0%, p-value: 0.974) and on code (mean increase: -2%, 95% CI: -10.0 to 7.0%, p-value: 0.286). Conclusions: The effect of badges at Biostatistics was a 7.6% increase in the data sharing rate, 5 times less than the effect of badges at Psychological Science. Though badges at Biostatistics did not impact code sharing, and had a moderate effect on data sharing, badges are an interesting step that journals are taking to incentivise and promote reproducible research.