Individual Dietary Diversity Score

The Individual Dietary Diversity Score (IDDS) is a simple, rapid count of the number of distinct food groups an individual consumed over the previous 24 hours, used as a population-level proxy for diet quality and micronutrient adequacy. Standardized in the FAO's 2011 Guidelines for Measuring Household and Individual Dietary Diversity by Kennedy, Ballard and Dop, the IDDS rests on the observation, reviewed by Ruel, that more diverse diets tend to be more nutritionally adequate. The score is obtained from a qualitative recall of everything eaten, mapping foods to a standard set of nine food groups and counting how many groups appear. Because it requires no portion weighing or food-composition tables, it is cheap to collect at scale and has become a workhorse indicator in nutrition surveys, food-security monitoring, and program evaluation.