Validity and Reliability of a Site-Level Assessment Questionnaire to Assess Nutrition and Physical Activity Practices in Schools.

Schools are an ideal setting for policy, systems, and environmental approaches to obesity prevention. Although school health environment assessments exist for planning purposes, we developed and tested a comprehensive questionnaire that is suitable for both evaluation and planning. Reliability was measured by comparing data collected by school personnel from low-income elementary schools across California at two time points, an average of 2 months apart ( = 23). To assess convergent validity, school responses were compared with the responses completed by the research team ( = 28). A weighted kappa test statistic and percent agreement were calculated for each question and specific groups of questions (questionnaire section, item topic, and response type). Test/retest reliability of the questionnaire yielded kappa statistics that ranged from -0.14 to 1.00 (interquartile range [IQR] 0.36). Percent agreement for reliability ranged from 34.78 to 100.00 (IQR 21.7). Kappa statistics for validity ranged from -0.14 to 1.00 (IQR 0.44). Percent agreement for validity ranged from 14.29 to 100.00 (IQR 39.2). Based on these findings, the tool was revised. Study findings indicate that the Site-Level Assessment Questionnaire as tested is a reliable and accurate instrument for use in low-income elementary schools. Revisions may have improved the validity and reliability. We therefore recommend either version for use to support low-income schools in their efforts to assess needs, evaluate progress, and create action plans; and to supply high-quality, aggregable data for large-scale analysis. Additional testing is recommended to validate the revised version, increase generalizability, and determine sensitivity to detect change over time.