Convergent validity of an activity-space survey for use in health research.

We explored the validity of a survey measuring activity spaces for use in health research in a racially/ethnically diverse adult sample (n = 86) living in four Chicago neighborhoods. Participants reported on the location and visit frequency of 64 activities and wore a GPS data logger. We assessed the spatial congruence of survey- and GPS-derived convex hull measures and the number of GPS points within 100 m and 1000 m of survey locations. The survey-derived convex hull measures captured a small percentage (median = 35.9%) of the GPS-derived convex hull area. However, most GPS points were located within 100 m or 1000 m of home or reported survey locations (median = 73.4% and 92.6%, respectively).