Supervision attributes • Supervisors participated in a group process with health care providers that involved discussing a problem and collaborating to find a solution • Supervisors received supervision • Supervisors received training • An explicit element of supervisory visits was that supervisors gave feedback to health care providers • Supervisors used a standard checklist during supervisory visits • Supervision frequency (i.e., number of visits per year). For studies with a duration that was not a multiple of 12 months, frequency was estimated as: number of visits during the study intervention period divided by the intervention period (in months) times 12 • Number of supervision visits during the study’s intervention period (i.e., supervision “dose”) Confounders • Baseline performance level • Time since supervision was conducted (in months)