Process evaluation of the Let's Move It intervention: protocol and results on implementation fidelity

Abstract

Background: A cluster-randomised trial tested the Let’s Move It multi-level intervention to promote youth physical activity and decrease sedentary behaviour in Finnish vocational schools in years 2015-17. A process evaluation is needed to illuminate trial findings and inform later dissemination. Our aims are to 1) describe the overall protocol for a process evaluation of Let’s Move It, and 2) report preliminary results on fidelity of intervention implementation. Methods: Data collection included semi-structured interviews with a subsample of students (n=36), focus group interviews with teachers (n=16), quantitative process data (fidelity and dose, as well as theorised causal mechanisms) for both students (n=1120) and teachers (n=120), online material usage data, interviews and field diaries regarding the school context. Qualitative and quantitative data will be analysed iteratively, and then triangulated with the results from the primary outcome evaluation. Findings: The Let’s Move It process evaluation protocol encompasses a comprehensive examination of causal mechanisms, implementation, and context. Out of intervention students, 80 % attended at least half of the 6 sessions. Altogether 64 teachers attended at least one sitting reduction workshop (out of 3). Intervention arm teachers reported having used sitting reduction strategies to decrease student total sitting time (p = .017) but not breaking up sitting (p = .050). Discussion: This talk demonstrates the potential of process evaluation in providing various insights for behavior change science. We point to key features in process evaluation such as the need to prioritise research questions to optimise scarce resources, accounting for the need to triangulate data.