As is typical for event occurrence data, our main outcome variable—number of days until relapse—was not normally distributed. Specifically, data obtained for this measure were found to be zero-inflated (due to those participants who did not stop smoking) and right censored (14.6% of observations were censored due to limited assessments over time that did not characterize relapse in all participants). Thus, survival methods were used to examine predictors of risk to relapse.
