Short-term temporal stability in observed retail food characteristics

Area of Science:

• Nutrition Science
• Public Health Research
• Food Environment Studies

Background:

• Direct observation is increasingly used to assess neighborhood retail food environments.
• Most studies rely on a single observation, potentially missing short-term variations.
• Understanding temporal stability is crucial for accurate food environment characterization.

Purpose of the Study:

• To evaluate the short-term (2-week) temporal stability of retail food availability, prices, and quality.
• To determine if repeated measures are necessary for accurate food environment assessment.
• To inform best practices for direct observation studies of food environments.

Main Methods:

• Conducted in-person observations of 157 food stores in Southwest Chicago, IL.
• Collected data at two time points, two weeks apart.
• Assessed availability, prices, and fresh produce quality for key food groups.

Main Results:

• Measures of food availability, prices, and fresh produce quality demonstrated general stability between the two observation periods.
• Statistical analyses (McNemar test, Wilcoxon signed-rank test) supported findings of temporal stability.
• No significant short-term fluctuations were detected in the assessed food environment metrics.

Conclusions:

• A single direct observation appears sufficient for accurately characterizing within-season food availability, prices, and fresh produce quality.
• This finding simplifies future research and monitoring of retail food environments.
• Supports the reliability of current methodologies using single observations in food environment research.