Study limitations
First, as a pragmatic trial, the CHORD implementation did not start or end on fixed days, because CHWs maintained continued contacts with their patients. As a result, some interventions, such as referrals, were delivered outside of the intervention period. We included them in this analysis if they were recorded by CHWs. Second, fidelity measures can be intervention specific. Therefore, the measures used in this study might not directly translate to other complex interventions. Third, one important aspect of implementation is how well the participants engage with the intervention. In our study, while we measured the delivery of core components from the perspective of CHWs, we could not assess the extent to which delivered interventions were received by patients. Fourth, with two CHWs per site, differences in approach and skill by the CHWs, despite their uniform training and monitoring, may have contributed to the differences by site. Fifth, with four CHWs, we did not have enough variation in race/ethnicity to track patient enrollment by the concordance of their race/ethnicity with that of CHWs’. Sixth, we report fidelity measures across the three waves of CHORD implementation, but do not examine changes in fidelity over time. Finally, while we report on fidelity delivery, our study did not measure fidelity receipt or fidelity enactment [