Identifying fast-food restaurants using a central register as a measure of the food environment

OBJECTIVE: To validate the identification and location of fast-food restaurants according to a government list of inspected food stores and restaurants.

METHODS: Fast-food restaurants in the Capital Region of Denmark were identified using a government list of inspected food stores and restaurants (the Smiley register, spring 2010). Ground-truthing was used as the validation method and was performed in May and June 2010 in 125 randomly selected 250×250 m grid cells.

RESULTS: A total of 186 fast-food restaurants was identified by ground-truthing and 99% of these were registered in the same grid cell by the Smiley register. However, only 152 restaurants of these were categorised as fast-food restaurants by both methods. The sensitivity was 82% and the positive predictive value was 92%. The mean±standard deviation position accuracy was 15±24 m.

CONCLUSIONS: Using a government list of inspected restaurants was found to be a valid and useful alternative to expensive and time-consuming field observation and provided a relatively accurate tool for identifying and locating fast-food restaurants in communities.