Estimated Average Requirement (EAR) is the average daily nutrient intake level that is estimated to meet the requirements of half - 50% - of the healthy individuals in a particular life stage and gender group.
Because the needs of the other half of the population will not be met by this amount, the EAR is increased by about 20% to arrive at the RDA.
Before setting the EAR, a specific criterion of adequacy is selected, based on a careful review of the literature. When selecting the criterion, reduction of disease risk is considered along with many other health parameters.