We repeated our analysis with modifications to avoid time-dependent bias, ie, restricting the exposure to events that occurred before the outcome. Two Cox regression time-to-event models with time-varying covariates were used to determine significant predictors of time until dropout. Our predictor of interest for model 1 was the time-varying cumulative average amount of SBHC use for all semesters up to and including the previous semester. As in our prior analyses, this was categorized into none, low (0.125-0.5 visits/semester), moderate (0.51-2.5 visits/semester), and high (>2.51 visits/semester) use. Contrary to our previous findings, SBHC use was not significantly related to dropout. Our predictor of interest for model 2 was the time-varying amount of SBHC use during the previous semester only, categorized into none, low/moderate (1-2 visits), and high (3 visits or more). Again, SBHC use was not significantly related to dropout. We apologize for this mistake.