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.
1University of Illinois at Chicago, College of Nursing, Department of Health Systems Science, Chicago, IL
2University of Illinois Urbana-Champaign, Department of Kinesiology and Community Health, Champaign, IL
3University of Iowa, College of Public Health, Ames, IA
4University of Illinois at Chicago, Institute for Health Research and Policy, Chicago, IL
Address for correspondence: Shannon N. Zenk, PhD, University of Illinois at Chicago College of Nursing, Department of Health Systems Science, 845 South Damen Ave, M/C 802, Chicago, IL 60612; Phone: (312) 355-2790; Fax: (312) 996-7725
ABSTRACT