A comprehensive coding system to measure the quality of school wellness policies.

In 2006, all local education agencies in the United States participating in the National School Lunch Program were required to establish school wellness policies that covered nutrition education, nutrition standards for school foods, and physical activity. The purpose of this psychometric study was to develop and evaluate the properties of a comprehensive and quantitative coding system to evaluate the quality of these policies. A 96-item coding tool was developed to evaluate seven goal areas: nutrition education, standards for US Department of Agriculture child nutrition programs and school meals, nutrition standards for competitive and other foods and beverages, physical education, physical activity, communication and promotion, and evaluation. Each goal area subscale and the total scale were scored on two dimensions: comprehensiveness and strength. Reliability was assessed by having pairs of researchers from four different states code a sample of 60 polices between July 2007 and July 2008. Goal area subscales were internally reliable (Cronbach's alpha=.60 to .93). Adequate interrater reliability scores were obtained at each level of scoring: total comprehensiveness and strength scores (intraclass correlation coefficient 0.82), subscale scores (intraclass correlation coefficient 0.70), and individual items (intraclass correlation coefficient 0.72). This coding system provided a reliable method for analyzing and comparing school district wellness policies in single or multistate studies.