Process Evaluation Tool Development and Fidelity of Healthy Retail Interventions in American Indian Tribally Owned Convenience Stores: the Tribal Health Resilience in Vulnerable Environments (THRIVE) Study

BACKGROUND: The Tribal Health Resilience in Vulnerable Environments (THRIVE) study aimed to increase healthy food access in 2 rural American Indian communities. The intervention sought to increase fruit and vegetable availability, variety, and convenience through placement, promotion, and pricing of healthy foods and beverages in tribal convenience stores. OBJECTIVE: The aim of this study was to describe the development and implementation of the study process evaluation tool to assess intervention fidelity as part of this cluster-controlled trial. METHODS: Eight stores (2 intervention and 2 control stores per Nation) participated in the study, implemented from May 2016 to May 2017. A web-based survey tailored to store layouts and intervention components assessed how often intervention items were available, approximate quantity available, and whether placement of healthier food items and promotional materials were implemented as designed. After pilot testing the survey, tribal staff members implemented it to collect process evaluation data in the 8 stores during a period of 9–12 mo, assessing study implementation and potential changes in control stores. RESULTS: Promotional materials were available ≥75% of the time for most intervention locations. Fruit availability was similar in Nation A and Nation B intervention stores (79–100% compared with 70–100%), whereas fresh vegetable availability was higher in Nation B compared with Nation A (95–96% compared with 55–75%). Both control stores in Nation A and 1 control store in Nation B had moderate fruit and vegetable availability, ranging from 45% to 52%. No control stores in either Nation used intervention promotional materials. CONCLUSIONS: Process evaluation data indicate that the study was implemented with moderate to high fidelity. The development and implementation of the tool can inform future healthy retail interventions that aim to improve rural and tribal food environments.