Implementation of the Norwegian school meal guideline: Development and reliability of two questionnaires to measure adherence.

This article reports on the development and reliability of two questionnaires that measure adherence to the Norwegian National Guideline on Food and Meals in School among primary schools and after-school services. Questionnaires for school principals and after-school leaders were developed systematically, using the following steps: (a) selection of scope, questions and adherence values; (b) face validity testing through expert review of initial drafts; (c) content validity testing through 19 cognitive interviews; (d) assessment of test-retest reliability in samples of principals ( = 54) and after-school leaders ( = 47); and (e) development of adherence indices. The cognitive interviews led to substantial revisions of the draft questionnaires, increasing content validity through improved relevance and clarity. Test-retest assessment showed that Cohen's κ ranged from -0.03 to 1.0 for principals and from -0.05 to 0.98 for after-school leaders, with 64 and 53% of values rated as 'substantial' or better. Percentage agreement averaged 85% among principals and 82% among after-school leaders. Intraclass correlation for the adherence index scores was 0.84 for principals and 0.91 for after-school leaders. Guideline adherence had a wide range in our samples, with an average of 71% for schools and 76% for after-school services. .