Measuring aspects of the environment related to availability and accessibility of healthy foods

The survey of instruments was completed and the chapter written by Melissa Smiley and Ana Diez Roux. It was last revised in May, 2005.

Introduction

The attached table summarizes articles demonstrating different ways to measure accessibility of grocery stores and availability of healthy foods.  While people are often encouraged to improve their health by eating healthier foods, it is important to understand how access and availability of food impact dietary choicest in different communities and neighborhoods.

The overall goal of this table is to identify a range of ways to measure one environmental risk factor (accessibility and availability of food) for cardiovascular disease.  The articles summarized in this table include measurement techniques to collect subjective and objective data.  The articles themselves, however, generally do not specifically address cardiovascular disease.  The table is focused exclusively on identifying and highlighting measurement techniques, and is not concerned with actual results calculated or correlations determined.

Key Elements in the Table

The following sections briefly describe the contents of each table column and the analysis criteria and definitions used in their creation.

Sources

Sources are arranged alphabetically by year, beginning with 2005.  Only articles published more recently than 1990 are included in the table.  We chose this year because significant research into the issues occurred throughout the 1990s.  Multiple sources are grouped into one table row when they utilized substantially similar or identical data and measurement technique.

This table is not an exhaustive collection of articles.  We consulted various databases, including PubMed, FirstSearch, the Avery Index to Architectural Periodicals, and Family and Society Studies Worldwide.  We systematically reviewed citations in articles in the table and articles that were considered but ultimately not included.   Once this process began to yield largely similar results, we were satisfied that we captured the majority of current work in this field.

Constructs

We identified two main constructs conveyed in the research.  Readers are invited to scan the table using these constructs to find measurements of interest.  The constructs are described below.

• Availability – These measurements focus on specific food items and determine whether they are sold, how much they cost, and what varieties and amounts are available.
• Accessibility – These measurements focus on counting numbers of food retailers (including stores and restaurants), determining where they are located, and calculating how they are distributed throughout geographic areas.

Note that slightly different definitions of availability and accessibility may be used by others.

Strategies

• Focus groups – Information on food access and shopping patterns are gathered by conducting focus groups in a neighborhood or community.
• Mapping – Locations of stores and/or restaurants are mapped for the purposes of identifying underserved areas.
• Observation (single item) – Observers visit stores for the purpose of measuring availability a particular product (usually milk).
• Observation (list) – Observers visit stores for the purpose of measuring availability of a collection of products, usually in the form of a shopping list.
• Statistical Analysis – New statistical measurements are created and calculated, using existing data sources and/or maps.
• Survey – Residents, shoppers, or grocery store managers are surveyed.

Measurement

This column contains a short summary of the actual steps taken to measure food access and/or availability.  For surveys, the number and types of survey items are listed.  For observations, the type of food and rationale for choosing it is included.

Validity/Reliability

Validity and/or reliability are noted with short descriptions, if applicable to the study.  Wherever possible, coefficients and correlations are included.  No mention is made if researchers merely noted that scales were previously tested or items had “face validity.”

General Comments and Areas for Further Research

Overall, there are innovative steps being taken to research things in this field.  This collection of articles and research strategies demonstrates ample room for more to be done.  As small towns and cities combat declining downtowns with new residential development, access and availability of food will be important.  It is also time to recognize the barriers to acquiring healthy food in neighborhoods where food access and availability has been consistently overlooked,

There are two main limitations of this collection of articles.  Detailed examinations of physical access to stores rarely address whether residents have the economic means of purchasing food.  Though some research includes cost considerations, much more can be done to examine disparities between the possibility of purchasing food and having the economic means to do it. A second limitation is that very few articles directly address how food availability and accessibility affect the dietary behavior of residents. Investigating this issue is especially complex because of the likelihood that reciprocal relationships are present.