ASA24® Resources Related to the Healthy Eating Index (HEI)
The Healthy Eating Index (HEI) is a measure of diet quality that researchers can use to assess compliance with the Dietary Guidelines for Americans. The HEI-2015 was introduced in 2018. There have been several prior versions, including the HEI–2010 and the HEI-2005. Information on calculating HEI scores from ASA24 data can be found on the HEI Overview of the Methods & Calculations web page. The HEI web pages also contain sample SAS code to calculate HEI scores for ASA24 data as well as for other dietary assessment tools.
There is a Canadian version of the HEI, but the information presented here pertains to the U.S. HEI only. Data based on ASA24-Canada-2016 can be used to calculate the U.S. HEI, however, Researchers may wish to consider whether this is appropriate for their research.
Calculating HEI Scores for Person-Level ASA24 Intake
It is important to consider that an HEI score at the individual or person level based on one or several days of intake data does not represent usual intake and that meeting dietary recommendations is meant to be achieved over time. However, methods have not yet been developed to estimate usual intake with recall or record data only. At this time, code available on the HEI website is only available to calculate HEI scores for one day or multiple days with the knowledge that this approach reflects intake on that given day and does not likely capture true usual intake.
SAS Code on the HEI website lets researchers calculate HEI scores in two ways:
- for each intake day, regardless of how many recalls or record days are available, per person
- one HEI score for each individual across all days of recalls or records, even if some respondents have varying number of intake days, including only one
There are two SAS programs to calculate HEI-2010, because the pyramid equivalents databases for ASA24-2016 and subsequent versions are different from those used for ASA24-2014 and prior versions (2016 and subsequent versions use USDA's Food Patterns Equivalents Database or FPED, and 2014 versions and prior use the MyPyramid Equivalents Database or MPED).
Additionally, if researchers using 2011, 2012 or 2014 versions of ASA24 are interested in calculating HEI-2015, FPED food groups equivalents must first be calculated from the data output. SAS code is available to perform this calculation.
Calculating HEI scores for Group-Level ASA24 Intake
Mean HEI scores for a population, subpopulation, or group can be estimated using ASA24 data and the population ratio method. This approach has been shown to be the preferred method of estimating a population's mean usual HEI component and total scores on the basis of a single day of data, which is sufficient for this purpose.
The HEI SAS Code page provides SAS programs to calculate mean and component HEI scores for a subpopulation or group using ASA24 output. Information is also provided on estimating distributions of HEI scores and on estimating relationships between HEI scores and another variable, such as health.
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