The statisticson food insecurity and hunger in U.S. households, published annually by the U.S. Department of Agriculture (USDA), are based on a survey measure developed by the U.S. Food Security Measurement Project, an ongoing collaboration among federal agencies, academic researchers, and private organizations. The measure was developed over the course of several years in response to the National Nutrition Monitoring Act of 1990. (A brief history of the development of the project is outlined in Chapter 2.)
One of the objectives of the development of the food security measure was to create a measure with generally agreed-on concepts, definitions, and measurement methodologies that could be used to estimate a standard and consistent indicator of the frequency and severity of problems regarding access to food in this country.
Each year since 1995, USDA has developed annual estimates of the prevalence of food security, food insecurity without hunger, and food insecurity with hunger for U.S. households. Food security for a household is defined as “access by all people at all times to enough food for an active, healthy life. Food security includes, at a minimum: (a) the ready availability of nutritionally adequate and safe foods and (b) an
assured ability to acquire acceptable foods in socially acceptable ways (e.g., without resorting to emergency food supplies, scavenging, stealing, or other coping strategies).” Food insecurity is defined as “limited or uncertain availability of nutritionally adequate and safe foods or uncertain ability to acquire acceptable foods in socially acceptable ways.” Hunger is defined as the “uneasy or painful sensation caused by a lack of food; the recurrent and involuntary lack of access to food” (Anderson, 1990, pp. 1575–1576).
The USDA estimates of the prevalence of food insecurity are developed using data collected annually in the Food Security Supplement to the Current Population Survey (CPS). The full supplement appears in Appendix A. The food insecurity questions—on whether the household experienced difficulty in meeting basic food needs due to a lack of resources, the severity of food deprivation ranging from “worry about running out of food” to “children ever not eating for a whole day,” and ways of augmenting inadequate food resources—are asked of all households with incomes below 185 percent of the poverty line. Thus households are presumed in USDA’s annual statistical reports to be fully food secure only if their annual incomes are higher than 185 percent of the poverty line and they gave no indication of food access problems on preliminary screener questions and are not asked the questions in the food security assessment series. The questions specify that any behavior or condition must be due to a lack of economic or other resources to obtain food, so the scale is not affected by hunger due to voluntary dieting or fasting or being too busy to eat or other reasons.
On the basis of the number of food insecure conditions that households report (the number of questions the respondent affirms), respondents are classified into one of three categories for purposes of monitoring and statistical analysis of the food security status of the population: food secure, food insecure without hunger, and food insecure with hunger. USDA uses statistical methods based on a single-parameter logistic item-response-theory model (the Rasch model) to assess individual questions and to assess the assumptions that justify using the raw number of items affirmed as an ordinal measure of food insecurity. (This method is described further in subsequent chapters.)
The USDA estimates, published in a series of annual reports, are widely used by government agencies, the media, and advocacy groups to report the extent of food insecurity and hunger in the United States, to monitor progress toward national objectives, to evaluate the impact of particular public policies and programs, as a standard by which the performance of USDA programs is measured, and as a basis for a diverse body of research relating to food assistance programs. Government agencies have also adopted the estimates as targets for performance assessment. The U.S. Department of Health and Human Services (DHHS) has included the food security measure to assess the performance of its Healthy People 2010 initiative. The Food and Nutrition Service of the USDA is using the measure as a target for its strategic plan to fulfill requirements of the Government Performance and Results Act of 1993 (Wilde, 2004a).
Despite the extensive use of the measure, some major questions related to the concepts themselves, the methodology, and their use, continue to be raised.
While the USDA annual reports define the concepts of food security and the three categories of food security that are estimated and reported (food secure, food insecure without hunger, and food insecure with hunger) and provide detail about how they are measured, the terms “food security” and “food insecurity” are relatively new to both policy makers and the public and are sometimes confusing. While the term “hunger” is not new, measurement of hunger and how hunger conceptually fits into food insecurity is not completely clear. As currently construed in USDA’s food security measure, hunger is considered a severe level of food insecurity. This use of the term “hunger” has been questioned by some who believe that hunger is conceptually separate from food insecurity. Because the label “hunger” is a politically potent concept, the methods used to classify households as food insecure with hunger are particularly important.
Methodological and technical issues about the measure of food insecurity generally concern the clarity, appropriateness, and design of the CPS survey questions. Critics question:
using a relatively long (12-month) reference period,
mixing questions focused on the household with questions focused on individuals,
using the raw score on the module to categorize households into one of the three food security categories, and
Using the same module to assess the food security of households with children and households without children.
Questions about the appropriate uses of the estimates of food security also have been raised. The primary use of the Food Security Supplement of the CPS is to estimate the prevalence of the categories of food security. The media and advocacy groups often interpret the prevalence estimates in language inconsistent with USDA usage. As currently measured, the estimates may not be appropriate for use in policy and program evaluations. Even if they are used, it would be helpful for their use to be consistent across federal government departments. The USDA strategic plan uses a food security target that differs from the DHHS Healthy People 2010 objectives, and the USDA annual performance reports omit the target altogether (Wilde, 2004a).
In addition, the Office of Management and Budget (OMB) has expressed concerns about the concepts and methods used by USDA for measuring food insecurity and hunger in its annual surveys. When approving the questionnaire for the conduct of the 2003 survey, OMB repeated its concerns by identifying key issues that needed to be addressed prior to the next survey.
The USDA’s food security measures were designed a decade ago in partnership with DHHS. USDA decided that a thorough review at this 10-year mark is warranted, especially in light of the persistent conceptual and methodological concerns. The Economic Research Service of USDA through its Food and Nutrition Research program has need for a review of the conceptualization and methods for measuring food insecurity monitoring, evaluation, and related research purposes and their validity and utility for informing public policy. Promotion of food security is part of the mission of USDA’s Food and Nutrition Service,
and certain food security measures constitute performance goals for that agency associated with the Government Performance and Results Act.
USDA requested the Committee on National Statistics (CNSTAT) of the National Academies to convene a panel of experts to provide an independent review of the current conceptualization and methods of measuring food insecurity and hunger in the U.S. population. The panel charge specifies that the 2-year study will be conducted in two phases. During Phase 1 of the study a workshop will be held to address the key issues laid out for the study and a short report will be prepared based on workshop discussions and preliminary deliberations of the panel. The specific tasks to be addressed in Phase 1 include:
the appropriateness of a household survey as a vehicle for monitoring on a regular basis the prevalence of food insecurity among the general population and within broad population subgroups, including measuring frequency and duration;
the appropriateness of identifying hunger as a severe range of food insecurity in such a survey-based measurement method;
the appropriateness, in principle and in application, of item response theory and the Rasch model as a statistical basis for measuring food insecurity;
the appropriateness of the threshold scores that demarcate food insecurity categories—particularly the categories “food insecure with hunger” and “food insecure with hunger among children”—and the labeling and interpretation of each category;
the applicability of the current measure of the prevalence of food insecurity with hunger for assessing the effectiveness of USDA’s food assistance programs, in connection with the performance goals pursuant to the Government Performance and Results Act (Public Law 103-62)1 for the Food and Nutrition Service; and
Future directions to consider for strengthening measures of hunger prevalence for monitoring, evaluation, and related research purposes.
In Phase 2 of the study the panel will consider in more depth the issues identified in Phase 1 relating to the concepts and methods used to measure food security and make recommendations as appropriate. In addition, the panel will address and make recommendations on:
the content of the 18 items and the set of food security scales based on them currently used by USDA to measure food insecurity;
how best to incorporate and represent information about food security of both adults and children at the household level;
how best to incorporate information on frequency and duration of food insecurity in prevalence measures;
needs and priorities for developing separate, tailored food-security scales for population subgroups, for example, households versus individuals, all individuals versus children, and the general population versus homeless persons; and
future directions to consider for strengthening measures of food insecurity prevalence for monitoring, evaluation, and related research purposes throughout the national nutrition monitoring system.
To address this two-phase request, CNSTAT appointed a panel of 12 members representing a range of expertise related to the scope of the study. This report addresses the panel’s mandate for Phase 1 only and provides the panel’s preliminary assessment of the food security measure and interim guidance for the continued production of the food security estimates. A final report with the panel’s conclusions and recommendations also will be prepared.
focus on the results of those activities, such as real gains in employability, safety, responsiveness, or program quality. Under the Act, agencies are to develop multiyear strategic plans, annual performance plans, and annual reports (U.S. Government Accounting Office, 2002).
During the first phase of the study, the panel reviewed a number of articles and papers prepared or sponsored by USDA to assess the methodological concerns about the food security measures and other published and unpublished papers.
The panel met on two occasions to deliberate on the issues listed above. The first meeting was held in March 2004. In the public part of the meeting, USDA staff and other experts in the field briefed the panel on the history of the conceptual and technical development of the measure and on the uses of the food security measure. Critics of the current measurement methodology presented their views, and USDA staff and other meeting attendees were given the opportunity to respond.
The panel held a large workshop, as called for in the contract, to obtain input from a wide range of researchers and other interested members of the public. The Workshop on the Measurement of Food Insecurity and Hunger was held on July 15, 2004. The agenda, presenters, and discussants for the workshop appear in Appendix B.
Four background papers were prepared by experts and presented at the workshop (the full text of the papers is available at http//www.nationalacademies.org/cnstat):
Conceptualization and Instrumentation of Food Security by J.P. Habicht, G. Pelto, E.A. Frongillo, and D. Rose;
The Uses and Purposes of the USDA Food Security and Hunger Measure by P. Wilde;
Item-Response Models and Their Use in Measuring Food Security and Hunger by M.S. Johnson; and
Alternative Construction of a Food Security and Hunger Measure from 1995 Current Population Survey Food Security Supplement Data by K. Alaimo and A. Froelich.
Discussants were asked to give their reactions to these papers, and open discussion sessions were set aside for general comments from participants. A roundtable discussion on the questionnaire design and cognitive aspects of the survey module was also held during the workshop.
ORGANIZATION OF THE REPORT
This interim report is limited to a preliminary examination of the tasks identified by USDA for Phase 1 of the study. The panel’s findings and conclusions are based primarily on the review of the literature to date, the presentations of the invited speakers and discussants, the public comments during the two public sessions, and the expert judgments of the panel.
Chapter 2 briefly reviews the background of the development of the food security measure and explains in more detail the concepts and methods used to estimate food security.
Chapter 3 addresses the questions posed to the panel and presents the panel’s findings to date, conclusions, and interim recommendations. The chapter concludes with an indication of the directions of the panel’s scope of work in Phase 2.