| Summary: | This dissertation investigated the substantive aspect of construct validity in the context of Canadian school tobacco policy ratings. The objective was to provide a better understanding of score meaning via the process of expert rater responding while rating school tobacco policies. Study one described Canadian school tobacco policies and identified policy characteristics. Written tobacco policies (N=196) were obtained from schools and boards across 10 Canadian provinces that participated in the Youth Smoking Survey. Policies were coded to identify characteristics associated with effectiveness in preventing student tobacco use. Smoking prevention education and cessation access were identified as key policy components that need to be addressed more strongly. Policy characteristics identified in study one formed the basis for study two. The objective of study two was to examine the cognitive processes that generate raters’ responses, identify rating obstacles and how raters overcome them. A think-aloud protocol was conducted with two expert tobacco policy raters who rated 12 tobacco policies using the Stephens & English rubric. Policies were sampled to reflect characteristics (type, length and comprehensiveness) identified in study one. Transcripts were coded to identify super-categories (rater behaviors), main categories (major cognitive processes at the item level) and subcategories to describe main processes in more detail. Categories and their interrelationships, rating obstacles and raters’ coping strategies are presented and a series of cognitive process models of rating is proposed. Findings suggest that raters use similar main processes explainable by similar sub-processes regardless of policy type rated. There was variation in rating obstacles and rater coping when different policy types were rated. The cognitive process models contribute to the substantive aspect of construct validity by providing explanations for score variation and enhancing understanding of score meaning. Explanation is sufficient when policies are comprehensive but is limited if based on short, less comprehensive policies. Implications for practice and policy recommendations are discussed.
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