PLEASE BE ADVISED... The data available from past USDA food consumption surveys reflect the foods and their nutrient values that were available at the time of the particular survey. Each survey was designed to assess the dietary status of the U.S. population at that particular time.
CHANGES IN METHODS AND OPERATIONS ACROSS SURVEYS...It is important to consider that survey methods and operations including questionnaire wording, data processing methods, and the survey nutrient database used to calculate the dietary intake were changed from survey to survey based on new data and methods available at the time. Comparing data across surveys must take into account these types of changes.
RESEARCH...There has been some research that addressed the impact of changes in methods and/or databases between selected surveys. References are included in the respective surveys' report section on this site.