Participant characteristics were described with the use of frequencies for categorical variables and means or medians for continuous variables. Differences between groups were tested with chi-square tests for categorical variables and one-way analysis of variance (ANOVA) for continuous variables. Differences in post-debriefing data release selections were examined with multinomial logistic regression which allows for polytomous instead of dichotomous outcomes, adjusting for potential confounders. Results were presented as odds ratios (OR) with 95% confidence interval (CI) comparing restricted or no data release to public data release. Participants’ age and the time lapse between consent and debrief were treated as continuous variables. All other factors included in the multivariate analysis were categorical variables; this included socio-demographics: gender, race and ethnicity, marital status, religious affiliation, education and income, and participant characteristics, including randomized consent type and consentee relationship (either adults providing consent for themselves or providing parental consent for their child). For all tests, a significance level of p < 0.05 (two-tailed) was used. All analyses were conducted using SPSS 17 or SAS 9.2 (SPSS, Inc., Chicago, IL; SAS Institute Inc., Cary, NC).
