2.4.1. Quantitative Responses
REGRESSION, REGRESSION
We summarized baseline characteristics of the study population overall and by study arm, as well as PROMIS measure outcomes by study arm at 12 months. We calculated each individual’s change in each PROMIS score from baseline (pre-pandemic) to 12 months (during pandemic) in order to carry out a difference-in-differences analysis of changes in PROMIS outcomes over time by study arm. We estimated differences between study arms in change-since-baseline in PROMIS T scores using mixed effects linear regression with study arm as the independent variable and a random effect for clinic. Regression analyses were adjusted for child age due to observed differences between study arms at baseline, both in the full sample (n = 501) and in the subset who responded to the 12-month survey (n = 401). To handle missing data, we compared baseline characteristics of participants missing 12-month primary outcome data to those not missing data and compared those missing primary outcome data in intervention group vs. control group [