title: Willingness to share research data is related to the strength of the evidence and the quality of reporting of statistical results.
abstract: BACKGROUND
  The widespread reluctance to share published research data is often hypothesized to be due to the authors' fear that reanalysis may expose errors in their work or may produce conclusions that contradict their own. However, these hypotheses have not previously been studied systematically.
  
  
  RESULTS
  We related the reluctance to share research data for reanalysis to 1148 statistically significant results reported in 49 papers published in two major psychology journals. We found the reluctance to share data to be associated with weaker evidence (against the null hypothesis of no effect) and a higher prevalence of apparent errors in the reporting of statistical results. The unwillingness to share data was particularly clear when reporting errors had a bearing on statistical significance.
  
  
  CONCLUSIONS
  Our findings on the basis of psychological papers suggest that statistical results are particularly hard to verify when reanalysis is more likely to lead to contrasting conclusions. This highlights the importance of establishing mandatory data archiving policies.
authors.affiliation: Psychology Department, Faculty of Social and Behavioral Sciences, University of Amsterdam, Amsterdam, The Netherlands. j.m.wicherts@uva.nl
authors.forename: Jelte M
authors.initials: JM
authors.lastname: Wicherts
authors.forename: Marjan
authors.initials: M
authors.lastname: Bakker
authors.forename: Dylan
authors.initials: D
authors.lastname: Molenaar
mesh_terms: D003299:Cooperative Behavior; D006801:Humans; D012106:Research
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