Development and reliability testing of a food store observation form

Area of Science:

• Nutrition Science
• Public Health Research
• Environmental Health

Background:

• Understanding the food store environment is critical for public health interventions.
• Existing tools for assessing food stores may lack reliability or comprehensive measures.
• Accurate data on product availability, pricing, and promotion is needed to evaluate food access.

Purpose of the Study:

• To develop and validate a reliable observational data collection instrument for food stores.
• The instrument aims to measure key aspects of the food retail environment, including product availability, pricing, and promotions.

Main Methods:

• Observational data collection was conducted in 120 food stores across the Chicago metropolitan area.
• The study included supermarkets, grocery stores, gas/convenience stores, and mass merchandise stores.
• Inter-rater reliability was assessed using Cohen's kappa coefficient for dichotomous variables and intra-class correlation coefficient for continuous variables.

Main Results:

• The instrument demonstrated substantial to almost perfect inter-rater reliability for most measures.
• Average kappa coefficients were 0.84 for product availability, 0.80 for interior, and 0.70 for exterior characteristics.
• Average intra-class correlation coefficients were 0.82 for pricing, 0.90 for fruit/vegetable options, and 0.85 for advertisements.

Conclusions:

• The developed instrument is a reliable tool for measuring the food store environment.
• While minor revisions may be needed, the instrument shows strong potential for use in research and public health surveillance.
• Reliable measurement of the food retail environment can inform strategies to improve food access and promote healthier diets.