Data analysis
REGRESSION, SECONDARY, SENSITIVITY
Participants’ characteristics were descriptively summarized and compared between the two scenario groups, using contingency tables and Chi-squared or Fisher’s exact test (with expected cell frequencies < 5). For the main objectives, differences between the scenarios were studied with Chi-squared or Fisher’s exact test (categorical outcomes), and with Wilcoxon rank-sum test (WTP). For the secondary objectives, associations between covariates and outcomes were assessed with Chi-squared or Fisher’s exact test (categorical outcomes), and with Wilcoxon rank-sum or Kruskal–Wallis test (WTP). Moderator analyses studied sociodemographic and reproductive covariates as potential effect modifiers of the association between scenarios and outcomes, using separate logistic regression analyses with interaction terms (for categorical outcomes) or stratified analyses (for WTP). Sensitivity analyses studied WTP differences between the scenarios in five subsets, obtained respectively after excluding respondents (A) with lower knowledge of OC, (B) not open to considering OC, (C) uncertain about the given WTP, or (D) providing outlier WTP values. The results of these analyses were plotted as medians with interquartile ranges (IQR), and as effect sizes (Cliff’s delta) with 95% confidence intervals (CI). An attrition analysis was conducted to compare characteristics of randomised respondents who did or did not complete the study. The statistical analyses were performed in R