Evaluating the Healthy Eating Index–2010
The performance of the HEI–2010 was evaluated by assessing its psychometric properties, including content validity, four types of construct validity, and one type of reliability.
Recent statistical advances allowed the estimation of the distribution of HEI scores calculated from distributions of "usual intake" (i.e., long-run daily average intakes). Because dietary recommendations are intended to be met over time rather than on any given day, this was an important advance. This portion of the evaluation was conducted using data for a sample of 8,262 National Health and Nutrition Examination Survey (NHANES) 2003-2004 respondents.
In addition, several sets of exemplary sample menus were scored using the HEI–2010, and the results were compared with those for the HEI–2005. The menus included those from the MyPlate website; the National Heart, Lung, and Blood's Dietary Approaches to Stop Hypertension (DASH); Harvard Medical School's Healthy Eating Pyramid; and the American Heart Association's 2005 No-Fad Diet.
Results of the evaluation showed that the HEI–2010 has both validity and reliability:
- Content validity: This type of validity indicates the extent to which a measure represents all facets of a construct. All of the key Dietary Guidelines food choice recommendations that relate to diet quality are reflected in HEI–2010 components. By design, the HEI does not cover other Dietary Guidelines recommendations, such as those for physical activity, body weight, and food safety.
- Construct validity: This type of validity evaluates whether an index measures what it is supposed to measure, and the HEI performed well on four types of construct validity. First, HEI–2010 scores between smokers and non-smokers were significantly different, indicating that the HEI can distinguish between groups with known differences in the quality of their diets. Second, an examination of Pearson's correlations of the HEI–2010 total and component scores with energy intake showed that the HEI can assess diet quality independently of diet quantity. Third, a principal components analysis demonstrated that multiple factors underlie the HEI–2010 and that both the individual components and the total score provide insights into diet quality. Finally, four sets of menus representing high-quality diets scored high on the HEI–2010.
- Reliability: Cronbach's coefficient alpha, used to assess internal consistency, indicated that the HEI–2010 measures an underlying construct of overall diet quality. Results of a principal components analysis showed that the individual component scores also are important because they provide additional insights into the quality of the diet beyond those of the total score.
Last Modified: 21 Apr 2014