Randomisation and data collection measures
Randomisation occurred at the end of the Engagement Period, with sites randomised in blocks of 4 to the Core or Enhanced intervention group, stratified by size (large vs. small). Allocation concealment was preserved for study sites and staff throughout the study. Service staff completed baseline (T0) questionnaires prior to randomisation and at T1 (6 months into implementation) and T2 (study close, after 12 months of implementation). A subsample also participated in semi-structured interviews at these timepoints. The purpose of questionnaires and interviews was to gather information about staff and organisational readiness, staff perception of the ADAPT CP such as its usefulness, appropriateness, and potential and actual barriers to implementation (these data are reported elsewhere [