Improving Data to Analyze Food and Nutrition Policies (2005)

Several changes in the United States over the past two decades have implications for diet, nutrition, and food safety, including patterns of food consumption that have produced an increase in overweight and obese Americans and threats to food safety from pathogens and bioterrorism. The changes raise a number of critical policy and research questions: How do differences in food prices and availability or in households’ time resources for shopping and food preparation affect what people consume and where they eat? How do factors outside of the household, such as the availability of stores and restaurants, food preparation technology, and food marketing and labeling policies, affect what people are consuming? What effects have food assistance programs had on the nutritional quality of diets and the health of those served by the programs? Where do people buy and consume food and how does food preparation affect food safety?

To address these and related questions, the Economic Research Service (ERS) of the U.S. Department of Agriculture (USDA) asked the Committee on National Statistics to convene a panel of experts to provide advice for improving the data infrastructure on food consumption and nutrition. The panel was charged to review data needs to support research and decision making for food and nutrition policies and programs in USDA and to assess the adequacy of the current data infrastructure and recommend enhancements to improve it. The panel was asked to consider improvements to current systems, not to propose major new systems. The panel’s

recommendations are based largely on the discussions at a workshop, which it sponsored in May 2004, to hear from USDA and other federal agencies with food and nutrition-related policy responsibilities and from statistical agencies and private firms that collect data on food consumption and expenditures.

No single data source currently provides or could provide all of the needed information. A number of data sources provide some of the information, but each has some weaknesses in addressing policy-related questions.

Relevant datasets fall under three categories:

1. federal datasets that are primary sources of data on food consumption, food expenditures, and dietary attitudes and knowledge:

• the National Health and Nutrition Examination Survey (NHANES), conducted by the National Center for Health Statistics on a continuing basis since 1999;

• the Continuing Survey of Food Intakes by Individuals (CSFII), last conducted by USDA in 1994-1996 (and again in 1998 for children under age 10), which was discontinued and then integrated into NHANES, beginning in 2002;

• the Diet and Health Knowledge Survey (DHKS), a past supplement to CSFII that was not part of the integrated NHANES-CSFII, but is a source of questions for a new supplement to NHANES under development by ERS, the Flexible Consumer Behavior Survey Module; and

• the Consumer Expenditure Survey (CE), conducted on a continuing basis since 1980 by the Bureau of Labor Statistics.

2. proprietary data collected by private market research firms to analyze food and related markets:

• retail and household scanner data, which include quantities sold and prices from bar codes on products purchased at retail outlets, for which the major producers are ACNielsen and Information Resources, Inc. (IRI);

• the National Eating Trends Survey, a small survey conducted by the NPD Group that obtains 14-day diaries of food intake; and

• the Consumer Report on Eating Share Trends (CREST), an online survey conducted by the NPD Group of people’s previous-day purchases of prepared foods.

3. other federal datasets that could provide useful information:

• the monthly Current Population Survey (CPS), which includes a December module on food expenditures, food assistance program participation, and food insecurity;

• the American Time Use Survey (ATUS), conducted by the Bureau of Labor Statistics, a new survey that plans to add a food and eating module (in cooperation with ERS);

• longitudinal (panel) surveys that provide repeated measurements on the same individuals, permitting analysis of changing behavior over time, such as the Early Childhood Longitudinal Study, the Health and Retirement Study of people over age 50, and the Panel Study of Income Dynamics, the longest running nationwide survey of families’ economic and demographic circumstances;

• surveys to which special modules to capture emerging trends can be added relatively easily, which include the Behavioral Risk Factor Surveillance System (BRFSS) and the State and Local Area Integrated Telephone Survey (SLAITS), both of which also provide state-level detail; and

• the Expanded Food and Nutrition Education Program (EFNEP), which helps low-income people provide nutritionally adequate meals for their families and collects information on their diet quality and food practices that may have research potential.

There are also several datasets that provide information relevant to food safety and awareness. The FoodNet system monitors outbreaks of food-related illness in ten sites. Periodically, the Food and Drug Administration asks people by telephone about food handling, food allergies, and consumption of potentially unsafe food in the Food Safety Survey and more broadly about awareness of relationships between diet and risks for chronic disease and health-related knowledge and attitudes in the Health and Diet Survey.

The multiplicity of sources of data related to food consumption, diet, and nutrition provide a range of information that is useful to policy makers

and researchers at USDA and other agencies with food-related responsibilities, which include agencies in the Department of Health and Human Services and the Environmental Protection Agency. Yet that multiplicity also results in overlaps that are not efficient and in gaps that limit the information that policy makers and researchers have to address current and emerging issues in food and nutrition.

Responding to our charge to assess and consider improvements to the current data systems, we offer six recommendations to improve knowledge about the nation’s changing patterns of food consumption. These broad recommendations are the basis for proposals for data enhancements throughout the report.

Recommendation 1: An interagency working group, led by the Office of Management and Budget, or co-led by an agency of the Department of Agriculture and the Department of Health and Human Services, should be established and take responsibility for the systematic development and use of diet and food consumption data to address policy and research questions of the federal government.

Recommendation 2: The proposed interagency working group should assign clear responsibilities to lead agencies for sustained programs of research and development on data in key areas to provide a sound base of scientific evidence for the group’s work to improve the available information on diet and food consumption.

Recommendation 3: The proposed interagency working group on diet and food consumption data should consider priorities and methods for obtaining additional food and nutrition-related information in the National Health and Nutrition Examination Survey. The development of the NHANES Flexible Consumer Behavior Survey Module, which will include questions on food expenditures, diet and health knowledge, and other food and nutrition-related topics, should proceed, and research should be conducted on ways to obtain price information for inclusion in NHANES.

Recommendation 4: The proposed interagency working group on diet and food consumption data should consider low-cost ways to enhance the analytic uses of NHANES and other surveys by linkages with food assistance program records and with sources of socioeconomic and food shopping characteristics for the areas in which survey respondents live. A

priority should be to work out effective ways to provide access to linked datasets through restricted access mechanisms, such as monitored remote on-line access.

Recommendation 5: The Economic Research Service of the U.S. Department of Agriculture should continue to explore the use of data on food purchases, prices, and consumption from proprietary retail scanner systems, household scanner panels, and household consumption surveys. This work should include a program to examine the quality of the data, consideration of ways to reduce the costs of access, and the determination of priority applications for the information.

Recommendation 6: The proposed interagency working group on diet and food consumption data should consider ways to enhance the usefulness of other federal datasets for food and nutrition-related policy analysis and research. Such datasets include the Current Population Survey, the American Time Use Survey, panel surveys that follow families, children, and the elderly over time, and surveys that are designed to include modules to track emerging trends.

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