Evaluating school obesity-related policies using surveillance tools: lessons from the ScOPE study

The evidence evaluating the association between school obestiy prevention policies and student weight is mixed. The lack of consistent findings may result, in part, from limited evaluation approaches. The goal of this article is to demonstrate the use of surveillance data to address methodological gaps and opportunities in the school policy evaluation literature using lessons from the School Obesity-Related Policy Evaluation (ScOPE) study. The ScOPE study uses a repeated, cross-sectional study design to evaluate the association between school food and activity policies in Minnesota and behavioral and weight status of youth attending those schools. Three surveillance tools are used to accomplish study goals: Minnesota School Health Profiles (2002-2012), Minnesota Student Survey (2001-2013), and National Center for Educational Statistics. The ScOPE study takes two broad steps. First, we assemble policy data across multiple years and monitor changes over time in school characteristics and the survey instrument(s), establish external validity, and describe trends and patterns in the distribution of policies. Second, we link policy data to student data on health behaviors and weight status, assess nonresponse bias, and identify cohorts of schools. To illustrate the potential for program evaluators, the process, challenges encountered, and solutions used in the ScOPE study are presented.