A data-sharing agreement helps to increase researchers' willingness to share primary data: results from a randomized...

Sharing individual participant data (IPD) among researchers, on request, is an ethical and responsible practice. Despite numerous calls for this practice to be standard, however, research indicates that primary study authors are often unwilling to share IPD, even for use in a meta-analysis. This study sought to examine researchers' reservations about data sharing and to evaluate the impact of sending a data-sharing agreement on researchers' attitudes toward sharing IPD.

To investigate these questions, we conducted a randomized controlled trial in conjunction with a Web-based survey. We searched for and invited primary study authors of studies included in recent meta-analyses. We emailed more than 1,200 individuals, and 247 participated. The survey asked individuals about their transparent research practices, general concerns about sharing data, attitudes toward sharing data for inclusion in a meta-analysis, and concerns about sharing data in the context of a meta-analysis. We hypothesized that participants who were randomly assigned to receive a data-sharing agreement would be more willing to share their primary study's IPD.

Results indicated that participants who received a data-sharing agreement were more willing to share their data set, compared with control participants, even after controlling for demographics and pretest values (d = 0.65, 95% CI [0.39, 0.90]). A member of the control group is 24 percent more likely to share her data set should she receive the data-sharing agreement.

These findings shed light on data-sharing practices, attitudes, and concerns and can be used to inform future meta-analysis projects seeking to collect IPD, as well as the field at large.