Below are topics that were raised during the panels and summarized in this final wrap-up session.
“Food access” was defined by presenters in various ways. A standard definition could help in making appropriate comparisons and furthering insight. One challenge is to resolve how the definition should incorporate such factors as geography, economics, and choice. If food access is determined using a spatial scale, the definition of “neighborhood” would benefit from further clarity and refinement.
Researchers reported on complementary instruments to measure food availability and affordability, including GIS, market basket surveys, other survey instruments, census data, and the Consumer Price Index. There is a strong desire (1) to develop and/or refine rigorous measures that are sensitive to the needs of diverse populations, and (2) to incorporate qualitative methods into research, in order to provide better information about issues such as consumer perceptions of food access.
Currently available data about food outlets from both public and private sources lack validation. Several presenters uncovered errors within national databases (such as those from Dun & Bradstreet and infoUSA) when they validated the measurement of these spatial data sets against actual visual measurements in specific neighborhoods, but it is unknown whether errors are random or somehow skewed to bias results. In addition, new census data, when available, will need to be used to investigate whether changes in the number of food outlets reflect population shifts. As noted above, the generalizability of local studies needs to be known before interventions can be applied on a broad scale.
Qualitative methods are also important for understanding the nuanced interaction between personal preferences and perceived access to quality food, which can then be compared to what is actually available. Challenges to understanding the links between food and health remain; they may best be met with multiple types of evidence from rigorous observational studies, natural experiments, simulations, and evaluations of evidence-based actions. Methods and tools from geography, demography, economics, psychology, sociology, urban planning, and policy can all help inform epidemiological research.