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Measuring Food Insecurity and Hunger: Phase 1 Report (2005)

Chapter: 2 The Food Security Measure

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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

2
The Food Security Measure

Prior to the development of the food security measure, there were widely varying estimates of the prevalence of hunger or lack of access to food and little consensus over which measure was most accurate. In 1984, the President’s Task Force on Food Assistance noted in its report the lack of a definition of hunger and lack of documentation of it in the United States. The task force report articulated the need for measuring hunger as follows (pp. 37, 39):

There is no official “hunger count” to estimate the number of hungry people, and so there are no hard data available to estimate the extent of hunger directly. Those who argue that hunger is widespread and growing rely on indirect measures…. We regret our inability to document the degree of hunger caused by income limitations, for such lack of definitive, quantitative proof contributes to a climate in which policy discussions become unhelpfully heated and unsubstantiated assertions are then substituted for hard information.

BACKGROUND

In 1990, the Life Sciences Research Office (LSRO) of the Federation of American Societies for Experimental Biology prepared a report

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

on the Core Indicators of Nutritional State for Difficult-to-Sample Populations for the American Institute of Nutrition under the provisions of a cooperative agreement with the U.S. Department of Health and Human Services (DHHS). This report was published in the Journal of Nutrition (Anderson, 1990). The report contains what have become the consensus definitions for food insecurity and hunger.

Also in 1990, the National Nutrition Monitoring and Related Research Act (NNMRR) was enacted (Public Law 101-445). Section 103 of the Act required the Secretaries of the Departments of Agriculture and Health and Human Services, with the advice of a board, to prepare and implement a 10-year comprehensive plan to assess the dietary and nutritional status of the U.S. population. Task V-C-2.4 in the plan specified (Federal Register 1993, 58:32 752–806):

Recommend a standardized mechanism and instrument(s) for defining and obtaining data on the prevalence of “food insecurity” or “food insufficiency” in the U.S. and methodologies that can be used across the NNMRR Program and at state and local levels.”

In response, a federal interagency working group comprising representatives from several federal agencies, academic researchers, private research institutions, and other stakeholders developed a food security survey module, a set of food security scales that combine information from sets of questions in the module, and a classification rule for characterizing the food security status of each household surveyed.

These measurement and monitoring activities had a number of policy-related objectives:

  • Provide objective, standardized information on the extent and severity of food insecurity and the characteristics of persons affected by them so that allocation of public resources and development of public policies and programs can be based on informed public debate. The mission statement of the Food and Nutrition Service, which administers the food assistance programs of the U.S. Department of Agriculture (USDA), includes the goal of increasing food security: “FNS increases food security and reduces hunger in partnership with cooperating orga-

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

nizations by providing children and low-income people access to food, a healthful diet, and nutrition education in a manner that supports American agriculture and inspires public confidence” (U.S. Department of Agriculture, 2005).

  • Provide data on household food security that can be used along with other information collected in surveys to assess the need for and effectiveness of public programs, especially food assistance programs; the causes of food insecurity at various levels of severity; and the effects of food insecurity on nutrition, health, children’s development, and other aspects of well-being.

  • Provide measures of food security for use in state, local, and special population surveys that can be compared meaningfully with national food security statistics.

USDA began measuring food security in 1995 with the first fielding of the Food Security Supplement to the Current Population Survey (CPS) by the U.S. Census Bureau.1 In working together to develop the supplement, USDA and DHHS sought advice from a large group of federal agencies, academic researchers, and private organizations. In 1994, the two agencies sponsored the First National Conference on Food Security Measurement and Research, which brought together experts from government, academia, and other researchers in the field. One of the key purposes of the conference was to develop consensus on the appropriate conceptual basis for a national measure of food insecurity. It also resulted in a working agreement about the best method for implementing the measure in national surveys (U.S. Department of Agriculture, 1995).

After extensive assessment of the food security questionnaire and field testing by the U.S. Census Bureau, a food security survey questionnaire was fielded by the bureau as a supplement to the CPS.

1  

The full Food Security Supplement includes more than 50 questions about food behavior and experiences. Within this supplement is a set of 10 questions for households with no children and 18 questions for households with children, which is used to estimate the prevalence of food insecurity.

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

USDA undertook a considerable amount of research. It convened an interagency working group composed of representatives of academia and policy research firms through a cooperative agreement to help develop and assess the household food security scale based on the supplement, to consider technical issues that arose in the development of the scale, and to produce a measurement scale for the severity of food insecurity (Hamilton et al., 1997a, 1997b). It also sponsored several technical reviews of food security measurement. In addition, it contracted with Mathematica Policy Research to use several years of data from the CPS Food Security Supplement to consider empirical issues that had arisen, such as the stability of the measurement scale over time, temporal adjustments to the categories for classifying the severity of food security, screening issues and imputation for missing data, among others (see Ohls, Radbill, and Schirm, 2001). Also, it had IQ Solutions assess methodological issues and provide guidance with a specific focus on the first five years of CPS data collection (see Cohen et al., 2002).

Finally, USDA contracted with a group of statisticians and economists at Iowa State University to consider various statistical issues in measuring food insecurity and hunger and specifically the statistical properties of the Rasch model, which is used to scale responses to the CPS Food Security Supplement (see Opsomer, Jensen, and Pan, 2003; Opsomer et al., 2002).

In 1999, USDA and DHHS hosted the Second Conference on Food Security Measurement and Research to develop priorities for future research and published the papers and proceedings of the conference (Andrews and Prell, 2001a, 2001b).

There is also a large body of literature from researchers both internal and external to USDA and DHHS covering methodological topics related to the measurement of food security. This research has prompted further refinements to the food security questionnaire—a shorter, 6-item food security module and measure, separate adult and child food security measures, a revised 30-day measure, and the translation of the survey module into Spanish.

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

CONCEPTS AND DEFINITIONS

Food insecurity is a concept that refers to the social and economic problem of lack of food due to economic deprivation, not voluntary fasting or dieting or for other reasons. The standard definition used in the United States for food insecurity is that “food insecurity exists whenever the availability of nutritionally adequate and safe foods or the ability to acquire acceptable foods in socially acceptable ways is limited or uncertain” (Anderson, 1990). This definition, supported by the ethnographic research conducted by Radimer et al. (1992), Wolfe, Frongillo, and Valois (2003), Hamelin, Habicht, and Beaudry (1999), Hamelin, Beaudry, and Habicht (2002), Quandt and Rao (1999), and Quandt et al. (2000, 2001), means that food insecurity is experienced when there is (1) uncertainty about future food availability and access, (2) insufficiency in the amount and kind of food required for a healthy lifestyle, and/or (3) the need to use socially unacceptable ways to acquire food.

Consequences of uncertainty, insufficiency, and social unacceptability are assumed to be part of the experience of food insecurity. Worry and anxiety typically result from uncertainty. Feelings of alienation and deprivation, distress, and adverse changes in family and social interactions also occur (Hamelin, Habicht, and Beaudry, 1999; Hamelin, Beaudry, and Habicht, 2002; Frongillo and Horan, 2004). Management strategies that people use to prevent or respond to the experience of food insecurity are conceptually different from food insecurity but are tied to it. “Hunger, in its meaning of the uneasy or painful sensation caused by a lack of food, is in this definition a potential, although not necessary, consequence of food insecurity” (Anderson, 1990, p. 1576).

As mentioned earlier, the Life Sciences Research Office has defined and published definitions of food security, food insecurity, and hunger (Anderson, 1990. pp. 1575-1576):

Food security: Access by all people at all times to enough food for an active, healthy life. Food security includes at a minimum (1) the ready availability of nutritionally adequate and safe foods and (2) 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).

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

Food insecurity: Limited or uncertain availability of nutritionally adequate and safe foods or limited or uncertain ability to acquire acceptable foods in socially acceptable ways.

Hunger: The uneasy or painful sensation caused by a lack of food, the recurrent and involuntary lack of access to food. Hunger may produce malnutrition over time…. Hunger … is a potential, although not necessary, consequence of food insecurity.

While the developers of the USDA’s food security supplement decided that food security was the most important concept to measure, some in the group charged with developing the measure of food insecurity specifically called for hunger to be part of the measurement project, because the use of estimates of the prevalence of hunger was thought to be an important device for advocacy (Habicht et al., 2004).

FOOD SECURITY MEASUREMENT

The Food Security Supplement to the Current Population Survey and the measurement scale are based on the underlying LSRO definitions. The Food Security Supplement contains a battery of questions for households responding to the CPS regarding various aspects of the availability and sufficiency of food. (The CPS is a representative national sample of about 60,000 households conducted monthly by the U.S. Census Bureau for the U.S. Department of Labor. It is based on a random sample of the civilian, noninstitutionalized population and is the primary source of information on labor force characteristics of the U.S. population.) The supplement has been conducted annually each year since 1995. From 1995 to 2000 the supplement alternated between April and August/September; beginning in 2001 it has been conducted in early December. While the full supplement includes more than 50 questions about food sufficiency and food security, only 10 (or 18 if there are children in the household) are used in the scale to estimate the prevalence of food security. These questions, asked of all households with incomes below 185 percent of the poverty line, generally ask about whether the household experienced anxiety over the lack of resources to meet basic food needs, the perception of inadequacy in quality or quantity of the diet, reduced food intake, or the feeling of hunger due to reduced food intake for adults and (sepa-

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

rately) for children. The questions are intended to measure both whether a household is “food secure” and the severity of food insecurity. The least severe form of food insecurity is worrying about getting enough food, and the most severe is skipping or cutting back on meals or losing weight because of lack of food. Each question references a specific time frame, either the past 12 months or the past 30 days, depending on the question. Separate scales are used for the different reference periods. The questions that comprise the food security scale are shown in Box 2-1.

BOX 2-1
Questions Used to Assess the Food Security of Households in the CPS Food Security Survey

  1. “We worried whether our food would run out before we got money to buy more.” Was that often, sometimes, or never true for you in the last 12 months?

  2. “The food that we bought just didn’t last and we didn’t have money to get more.” Was that often, sometimes, or never true for you in the last 12 months?

  3. “We couldn’t afford to eat balanced meals.” Was that often, sometimes, or never true for you in the last 12 months?

  4. In the last 12 months, did you or other adults in the household ever cut the size of your meals or skip meals because there wasn’t enough money for food? (Yes/No)

  5. (If yes to Question 4) How often did this happen—almost every month, some months but not every month, or in only 1 or 2 months?

  6. In the last 12 months, did you ever eat less than you felt you should because there wasn’t enough money for food? (Yes/No)

  7. In the last 12 months, were you ever hungry, but didn’t eat, because you couldn’t afford enough food? (Yes/No)

  8. In the last 12 months, did you lose weight because you didn’t have enough money for food? (Yes/No)

  9. In the last 12 months did you or other adults in your household ever not eat for a whole day because there wasn’t enough money for food? (Yes/No)

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

The questions in the food security module specify that any behavior or condition must be due to a lack of economic or other resources to obtain food. The scale, therefore, is not affected by insecurity and hunger due to voluntary dieting or fasting or being too busy to eat or other reasons, as mentioned earlier. The panel recognizes that there are other important sources of deprivation not entirely driven by economic resources, such as the quality of food intake or nutrition, or lack of access to acceptable food options. Quality is important, but beyond the scope of this report. Moreover, measurement of such an expanded

  1. (If yes to Question 9) How often did this happen—almost every month, some months but not every month, or in only 1 or 2 months?

(Questions 11-18 are asked only if the household included children age 0-18)

  1. “We relied on only a few kinds of low-cost food to feed our children because we were running out of money to buy food.” Was that often, sometimes, or never true for you in the last 12 months?

  2. “We couldn’t feed our children a balanced meal, because we couldn’t afford that.” Was that often, sometimes, or never true for you in the last 12 months?

  3. “The children were not eating enough because we just couldn’t afford enough food.” Was that often, sometimes, or never true for you in the last 12 months?

  4. In the last 12 months, did you ever cut the size of any of the children’s meals because there wasn’t enough money for food? (Yes/No)

  5. In the last 12 months, were the children ever hungry but you just couldn’t afford more food? (Yes/No)

  6. In the last 12 months, did any of the children ever skip a meal because there wasn’t enough money for food? (Yes/No)

  7. (If yes to Question 16) How often did this happen—almost every month, some months but not every month, or in only 1 or 2 months?

  8. In the last 12 months did any of the children ever not eat for a whole day because there wasn’t enough money for food? (Yes/No)

SOURCE: Nord, Andrews, and Carlson (2004)

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

definition will likely need quite different kinds of study designs and samples.

Multiple questions are used for three main reasons. First, although food insecurity as defined by USDA extends across a range of severity, the common-language descriptions of the manifestations or indicators of food insecurity extend across a narrow range of severity. For example, hunger in common-language terms refers only to a small range of the most severe conditions in the questions. Combining these descriptions or indicators in a single scale allows measurement of the phenomenon across its range of severity. Second, a general strength of multiple-question measures is that relationships of the questions to the underlying phenomenon (food insecurity) can be inferred from the relationships among the questions. Third, a set of questions provides more reliable measurement than can any single question.

Households are classified into the three categories of food insecurity for purposes of monitoring the food security status of the population. These categories are used in part because they characterize household situations that are easier for the public and policy makers to understand than an abstract number, such as an average level of food insecurity.

USDA uses the Rasch model to select and order questions by the severity of food insecurity that they indicate, so that responses can then be summed to arrive at the categories of food insecurity. The Rasch model is a single parameter logistic item response theory model. (See Chapter 3, pp. 7–13 for a brief description of the basics of the IRT model. For more detail the reader is referred to the paper prepared by M.S. Johnson for the workshop in 2004.) The ranges of each category and the number of affirmed items necessary to be in a given category are detailed in Box 2-2.

A primary purpose of the food security measures is to estimate the prevalence of food insecurity in the country. USDA publishes a report each year summarizing the results of the latest collection round of the Food Security Supplement.2Table 2-1 provides estimates of the per-

2  

The latest in this series is Nord, Andrews, and Carlson (2004).

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

BOX 2-2
Categorization of Food Security Status of Households According to the Number of Affirmed Items on the Food Security Scale

Households without children (based on responses to the 10 adult and household items):

  • Food secure = households that denied all items or affirmed 1 or 2 items

  • Food insecure without hunger = households that affirmed 3, 4, or 5 items

  • Food insecure with hunger = households that affirmed 6 or more items

Households with children (based on responses to all 18 items):

  • Food secure = households that denied all items or affirmed 1 or 2 items

  • Food insecure without hunger = households that affirmed 3 to 7 items

  • Food insecure with hunger = households that affirmed 8 or more items

centage of households and individuals who are food secure, food insecure without hunger, and food insecure with hunger for the years 1998-2002 based on the CPS survey.

For a concept that is relatively new, the food security measure has influenced policy making and the understanding of behavior and perceptions regarding the lack of resources to obtain food. The annual reports of the estimates of food security are consistently met with interest by the media. There is also growing interest in widening the use of the estimates for program performance assessments and for program evaluation.

The next chapter discusses the panel’s findings to date relating to some of the tasks identifies for the panel’s consideration and its preliminary assessment based on these findings. The chapter also makes some interim recommendations for USDA’s consideration while the panel undertakes more extensive investigation of the issues in Phase 2 of the study.

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

TABLE 2-1 Prevalence of Food Security, Food Insecurity, and Hunger by Year (Percentage)

Unit

Food Secure

Food Insecure Without Hunger

Food Insecure With Hunger

Households

1998

88.2

8.1

3.7

1999

89.9

7.1

3.0

2000

89.5

7.3

3.1

2001

89.3

7.4

3.3

2002

88.9

7.6

3.5

2003

88.8

7.7

3.5

All individuals (by food security status of household)*

1998

86.5

9.8

3.7

1999

88.5

8.6

2.9

2000

87.9

9.0

3.1

2001

87.8

8.9

3.3

2002

87.5

9.1

3.4

2003

87.3

9.3

3.4

Adults (by food security status of household)*

1998

88.8

7.9

3.3

1999

90.5

7.0

2.5

2000

89.9

7.3

2.8

2001

89.8

7.3

3.0

2002

89.5

7.5

3.0

2003

89.2

7.7

3.1

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×

Unit

Food Secure

Food Insecure (Without hunger among children)

Food Insecure (With hunger among children)

Households with children

1998

82.4

16.7

0.9

1999

85.2

14.2

0.6

2000

83.8

15.5

0.7

2001

83.9

15.6

0.6

2002

83.5

15.8

0.7

2003

83.3

16.1

0.5

Children (by food security status of household)

1998

80.3

18.7

1.0

1999

83.1

16.2

0.7

2000

82.0

17.2

0.8

2001

82.4

16.9

0.6

2002

81.9

17.3

0.8

2003

81.8

17.6

0.6

*The food security survey measures food security status at the household level. Not all individuals residing in food-insecure households are appropriately characterized as food insecure. Similarly, not all individuals in households classified as food insecure with hunger, nor all children in households classified as food insecure with hunger among children, were subject to reductions in food intake or experienced resource-constrained hunger.

SOURCES: Calculated by the Economic Research Service using data from the August 1998, April 1999, September 2000, December 2001, December 2002, and December 2003 Current Population Survey Food Security Supplements.

Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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Suggested Citation:"2 The Food Security Measure." National Research Council. 2005. Measuring Food Insecurity and Hunger: Phase 1 Report. Washington, DC: The National Academies Press. doi: 10.17226/11227.
×
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