Dietary Reference Intakes (DRIs) are the most recent set of nutrient-based reference values, which, together with recommended dietary assessment methods, are being used to update estimates of nutrient adequacy of population subgroups. Recent estimates suggest both dramatic dietary deficiencies and excesses for selected nutrients among some subgroups. This report takes a critical look at the studies and methods used to set DRIs. The findings show that errors in dietary recall data—either underreporting or overreporting of intakes—may partially explain the inadequacies and excessive intakes. In addition, the lack of sensitive, specific biochemical markers has resulted in DRIs for selected nutrients to be based on less than optimal data. Because the DRIs are used by food and nutrition assistance programs to set nutritional objectives, establish program benefits, and evaluate program outcomes, it is important to understand the issues involved in deriving the DRIs and how to interpret the results of dietary assessments.