Development and Psychometric Evaluation of the Perceived Diet Quality Questionnaire

Perceived diet quality (PDQ), measured with a single question, has been linked to better cardiometabolic health indicators. However, no published comprehensive tool to measure PDQ exists. Therefore, the objective of this study was to describe the development and initial psychometric evaluation of a novel tool to measure perceived diet quality (PDQ).

Development included focus groups (n = 27) and thematic analysis. Psychometric evaluation included expert reviews (n = 3), cognitive interviews (n = 13), and online cross-sectional nonexperimental survey (n = 605). Eleven items-with 3 addressing perceived diet quality based on qualitative, graded, and numeric ratings, and satisfaction with diet healthfulness, balanced meals, meal planning/preparation, nutrition knowledge, home cooking vs. eating out/takeout, food label use, difficulty eating healthy, and guilt/regret about food choices comprising the other items. Analysis included exploratory factor analysis, concurrent and convergent validity, and construct reliability.

Seven of the 11 variables were retained for final factor solution. Mean (SD) of PDQ Scale, possible score range 6.5-35 points, was 22.6 (5.4). Construct reliability was demonstrated by McDonald's omega of 0.91. Concurrent validity was demonstrated by correlation of 0.74 between single qualitative PDQ item (current assessment method) and PDQ Scale. Weak to moderate convergent validity was demonstrated by correlations of 0.31 and 0.51 between the PDQ Scale and diet quality scores measured using the Healthy Eating Index and Global Dietary Recommendations, respectively. Correlations were generally significantly higher than correlations with single qualitative PDQ item.

The PDQ Scale may be better measure of self-assessed diet quality than the current single qualitative item.