The third School Nutrition Dietary Assessment Study (SNDA-III) confronts transformations in the school food environment and evolving nutrition standards with a range of precise research methods. 

U.S. Department of Agriculture (USDA)-sponsored school meal programs subsidize the nourishment of over 40 million students every day. Since the early 1990s, USDA has conducted periodic evaluations of both the National School Lunch Program (NSLP) and the School Breakfast Program (SBP). The first assessment prompted the School Meals Initiative for Healthy Children (SMI), an extension of the Dietary Guidelines for Healthy Americans 1995. The second School Nutrition Dietary Assessment (SNDA-II) found insufficient progress in meeting the 1995 requirements. SNDA-III focused on the 2004–2005 school year. 

SNDA-III used a three-stage approach, gathering information at the school food authority level, the school level and the student level. Field interviewers obtained data at the student level through 24-hour dietary recalls, conducted in-person interviews with food service managers and principals, and used checklists to collect information on competitive foods.  Food service managers, responding to menu surveys, received support from experienced interviewers who themselves were given feedback and training from study nutritionists.

SNDA-III features several analytical adaptations developed to meet the challenges posed by new menu planning systems and problems in estimating nutrient intakes for individuals.