presented the evidence on relationships between participation in the Supplemental Nutrition Assistance Program (SNAP) and the potential for participants to achieve the program goals of improving food security and access to a healthy diet. This chapter presents evidence on individual, household, and environmental factors that affect food purchasing and consumption decisions and their impact on food choices and access and ultimately on the adequacy of SNAP allotments for achieving those goals. First, however, the chapter describes household food production theory as a framework for the discussion of these factors. After a brief review of the data and analytical challenges to research designed to broaden understanding of the issues facing SNAP participants, the final section presents a summary of findings and conclusions.
It should be noted that, in evaluating the available evidence, the committee determined it would be most useful to examine research questions with a focus on observational studies. This is because randomized controlled trials are infrequent among the types of studies considered. Much of the observational evidence available was cross-sectional, and the findings from these studies were considered in the context of the total available evidence, including that from both observational and experimental studies. All studies reviewed were evaluated by content area, study design, and publication source. Although they were not given equal weight with peer-reviewed publications, some publications from nongovernmental organizations and stakeholder groups also were considered because of the additional insight they provided into the behavioral aspects of participation in nutrition assistance programs. The committee's literature search strategy is described in Appendix D.
HOUSEHOLD PRODUCTION THEORY AS AN ORGANIZING FRAMEWORK
Consumers choose foods for consumption within the context of their own and their household's preferences and available resources. According to basic economic theory, households purchase foods and other market goods to maximize utility, or well-being, based on their preferences and subject to the constraint that the cost of those goods is less than or equal to the sum of all sources of income. However, households are subject not only to an income constraint but also a time constraint. Thus, according to household production theory, households combine time and market goods to produce commodities for consumption in the household (Becker, 1965).
