Population Ratio Method
For more information, read an Overview of the Methods & Calculations.
The steps of the population ratio method are:
Deriving Sums. For each HEI component, dietary constituents are summed together (e.g., Greens and Beans is created from the sum of dark green vegetables and legumes (beans and peas)).
For the HEI-2015, the components and associated dietary constituents are noted below:HEI-2015 Components and Associated Dietary Constituents
Components Units Dietary Constituents From FPED (or other food-based database) Whole Fruits cup eq. Citrus, Melons, Berries + Other Intact Fruits Total Fruits cup eq. Total Fruit Greens and Beans cup eq. Dark Green Vegetables + Legumes (Beans and Peas) in cup equivalents Total Vegetables cup eq. Total Vegetables + Legumes (Beans and Peas) in cup equivalents Whole Grains oz. eq. Whole Grains Refined Grains oz. eq. Refined Grains Dairy cup eq. Total Dairy Seafood and Plant Proteins oz. eq. Seafood (high in n-3) + Seafood (low in n-3) + Soy Products + Nuts and Seeds + Legumes (Beans and Peas) in oz equivalents Total Protein Foods oz. eq. Total Meat, Poultry, and Seafood (including organ meats and cured meats) + Eggs + Nuts and Seeds + Soy + Legumes (Beans and Peas) in oz equivalents Added Sugars tsp. eq. Added Sugars From FNDDS (or other nutrient database) Fatty Acids g (Total Monounsaturated Fatty Acids + Total Polyunsaturated Fatty Acids)/Total Saturated Fatty Acids Saturated Fats g* Total Saturated Fatty Acids Sodium mg Sodium Energy kcal Total Energy
cup eq.=cup equivalents; oz. eq.=ounce equivalents; tsp. eq.=teaspoon equivalents; g=grams; g*= fatty acids are calculated in grams but converted to energy in the scoring process; mg=milligrams
Calculating Means. The means of each of the dietary constituents across individuals are computed. When more than one 24HR is available, the score is calculated in the same manner, using both recalls for a participant.
Constructing Ratios. The appropriate ratios are constructed for the population. Usually these are the ratios of the dietary constituents to 1000 kcal of energy, with the exception of fatty acids, which use the ratio of the sum of monounsaturated and polyunsaturated fatty acids to saturated fatty acids. (Also, note two components are expressed on a percent of calories basis. Therefore, grams of saturated fat should be multiplied by 9 to convert g to kcal, and added sugars should be multiplied by 16 to convert teaspoons to kcal, prior to dividing by total energy).
Scoring. Each ratio is scored according to the algorithm. The component scores are summed to calculate the total score.