Content validity and reliability of a university food environment assessment instrument

This study aimed to evaluate the content validity and reliability of an instrument for evaluating the university food environment. A checklist was developed to assess establishments that sell food and beverages in the university environment. The content validation encompassed the development of the instrument, expert evaluation and pretest performance. Reliability was evaluated using a convenience sample (n=64) of establishments distributed across seven campuses of three public universities and was carried out using interobserver (IO) and test-retest (TR) evaluations. Categorical and count variables were analyzed by calculating the percentage agreement (PA), kappa coefficient (k) and prevalence-adjusted, bias-adjusted kappa (ka), and continuous variables were analyzed by the intraclass correlation coefficient (ICC). The checklist consisted of 204 items distributed in seven domains. The instrument's performance was considered excellent or very good for 91.3% (PA) of the items when evaluated. For IO, 68.3% (k) and 96.5% (ka) had excellent, very good or good agreement, while for TR, 65% (k) and 96.5% (ka) had excellent agreement. The instrument showed satisfactory content validity and reliability for characterizing the food environment at Brazilian universities.