Mobile applications enhance wellness interventions. Applications that depend on location for intervention delivery may experience challenges associated with functionality. The objective of this abstract is to share information learned while developing a smartphone program to encourage users to make healthy choices when they enter an eating venue by delivering tailored messages.


The application uses location services to detect users’ position relative to centroid coordinates in a database of known eating venues. The location radius was originally set to deliver a notification of a message within 50 meters of an eating venue (entries measured at this distance, N=62) and later was restricted to 25 meters (N=62). During testing users dwelled at a location for 5 minutes then compared the coordinates of the location services marker with the location of the user. They then recorded whether or not notifications were received 1) on the users’ phones and 2) inside or outside of the eating venue. They also 3) compared the variance of notification receipt at both radii.


Overall, out of 124 tests, the location services tracking was accurate approximately two thirds of the time (67%) with accuracy defined as whether the marker indicated where the user actually was at the time of the test. Users received notifications 82% of the time (total number of notifications received N=102). Using the 50-meter radius setting, 79% of notifications were received inside the fast food restaurant compared to 85% using the 25-meter radius setting.


Using location services to trigger message delivery is a promising way to enhance health behavior interventions. However, limitations exist in the ability of mobile phone technology to successfully detect a users’ precise location. Adjusting the geo-radius may reduce ‘false positives’ and avoid delivery of a message at a location that was not intended. Further work is required to explore factors that impact accuracy.