Jelte M. Wicherts, Marjan Bakker, Dylan Molenaar have published "Willingness to Share Research Data Is Related to the Strength of the Evidence and the Quality of Reporting of Statistical Results" in PLoS ONE.
Here's an excerpt:
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.