Short-term Temporal Stability in Observed Retail Food Characteristics

Abstract 

Objective

Use of direct observation to characterize neighborhood retail food environments is increasing, but to date most studies have relied on a single observation. If food availability, prices, and quality vary over short time periods, repeated measures may be needed to portray these food characteristics. This study evaluated short-term (2-week), within-season temporal stability in retail food availability, prices, and quality.

Design

In-person observations of retail food stores at 2 time points, 2 weeks apart.

Setting

Southwest Chicago, IL.

Sample

157 food stores.

Main Outcome Measures

Availability and prices of food items selected from the following food groups: fruit, vegetables, grains, meats and beans, and dairy, as well as fresh produce quality.

Analysis

Temporal stability was tested for availability using a McNemar test and for price and quality using a Wilcoxon signed-rank test.

Results

Measures of food availability and prices as well as fresh produce quality at stores were generally stable at the 2 time points.

Conclusions and Implications

This study suggests that a single observation may be sufficient to accurately characterize within-season food availability, food prices, and fresh produce quality.

Key Words: food environment, measurement, food prices, food supply, reliability, food quality