JMIR Publications

ABSTRACT

Background:

Consumer food environments are increasingly being recognized as influential determinants of food purchasing and subsequent intake and health. We developed a tool to enable efficient, but relatively comprehensive, appraisal of the in-store food environment. The Store Scout mobile app facilitates evaluation of product (availability, range), placement (visibility, accessibility, proximity to high-traffic areas, location relative to other products), price (price promotion) and promotion (displays, advertising) across seven categories of food products with appraisal given immediately as scores (0-100; where higher is more in line with best practice).

Objective:

We aimed to evaluate reliability (inter-rater reliability and internal consistency) and utility (distribution of scores, variation by store type) of measurements using the Store Scout mobile app.

Methods:

Two surveyors used the Store Scout mobile app to evaluate the store environment independently in 54 stores; 34 metropolitan stores (9 small and 11 large supermarkets, 10 convenience stores and 4 petrol stations in Brisbane, Australia) and 20 remote Indigenous community stores (19 small supermarkets and 1 petrol station) in Northern Australia. Agreement between surveyors in overall and category scores was evaluated using intraclass correlation coefficients. Interrater reliability of measurement items was assessed using percentage agreement and Gwet’s agreement coefficient (AC). Internal consistency was assessed by comparing responses of items measuring similar aspects of the store environment. We examined distribution of score values using boxplots and difference by store type using Kruskal-Wallis test.

Results:

There was 83.2% agreement across all measurement items (n=8584/10312). Median difference between surveyors in overall score was 4.4 (range 0-11.1) with intraclass correlation coefficient of 0.954 (95% confidence interval 0.914-0.975). Most measurement items had very good (38%; n=74/196) or good (41%; n=81/196) inter-rater reliability using Gwet’s AC. Minimal inconsistency of measurement was found. Overall scores ranged from 19.2 to 81.6. There was a significant difference in score by store type (p=0.0001). Large Brisbane supermarkets scored highest (median 77.4; range 53.2-81.6); small Brisbane supermarkets (63.9 ;41.0-71.3) and small remote Indigenous community supermarkets (63.8; 56.5-74.9) scored significantly higher than Brisbane petrol stations (33.1; 19.2-37.8) and convenience stores (39.0; 22.4-63.8).

Conclusions:

These findings suggest good reliability and internal consistency of food environment measurements using the Store Scout mobile app. We identified specific aspects that can be improved to further increase the reliability of this tool. We found good distribution of score values and evidence that scoring could capture differences by Store Type. The Store Scout mobile app shows promise in its capability to measure and track health enabling characteristics of store environments. Clinical Trial: Australian New Zealand Clinical Trials Registry ACTRN12618001588280