Randomization and masking
PCP
Eligible PCPs were randomly assigned to the intervention and control arms on a 1:1 basis leveraging the stratified block randomization technique. This technique, rather than the block randomization originally stated in the protocol, was used to ensure that PCPs were uniformly distributed between the study arms with respect to the baseline value of the primary outcome. The decision to use this technique was made before the first PCP was recruited. The statistical analysis plan was updated accordingly to reflect this change. The stratification variable was based on the percentage of encounters (visits) in which an antibiotic was dispensed by PCPs at baseline (details of how this information was collected are in the “Outcomes” section). It had three strata: low, moderate, and high. PCPs that dispensed antibiotics in < 70%, 70-89%, and ≥ 90% of visits at baseline were, respectively, categorized into the low (four PCPs), moderate (ten PCPs), and high (six PCPs) strata. Each stratum had a separate list. The random sequence for each stratum (consisting of 1s and 2s) was generated using a research randomizer 