TY - JOUR
T1 - Validation of a GIS Facilities Database
T2 - Quantification and Implications of Error
AU - Boone, Janne E.
AU - Gordon-Larsen, Penny
AU - Stewart, James D.
AU - Popkin, Barry M.
PY - 2008/5
Y1 - 2008/5
N2 - Purpose: To validate a commercial database of community-level physical activity facilities that can be used in future research examining associations between access to physical activity facilities and individual-level physical activity and obesity. Methods: Physical activity facility characteristics and locations obtained from a commercial database were compared to a field census conducted in 80 census block groups within two U.S. communities. Agreement statistics, agreement of administratively defined neighborhoods, and distance between locations were used to quantify count, attribute, and positional error. Results: There was moderate agreement (concordance: nonurban: 0.39; urban: 0.46) of presence of any physical activity facility and poor to moderate agreement (κ range: 0.14 to 0.76) of physical activity facility type. The mean Euclidean distance between commercial database versus field census locations was 757 and 35 m in the nonurban and urban communities, respectively. However, 94% and 100% of nonurban and urban physical activity facilities, respectively, fell into the same 5-digit ZIP code, dropping to 92% and 98% in the same block group and 71% along the same street. Conclusions: Our findings suggest that the commercial database of physical activity facilities may contain appreciable error, but patterns of error suggest that built environment-health associations are likely biased downward.
AB - Purpose: To validate a commercial database of community-level physical activity facilities that can be used in future research examining associations between access to physical activity facilities and individual-level physical activity and obesity. Methods: Physical activity facility characteristics and locations obtained from a commercial database were compared to a field census conducted in 80 census block groups within two U.S. communities. Agreement statistics, agreement of administratively defined neighborhoods, and distance between locations were used to quantify count, attribute, and positional error. Results: There was moderate agreement (concordance: nonurban: 0.39; urban: 0.46) of presence of any physical activity facility and poor to moderate agreement (κ range: 0.14 to 0.76) of physical activity facility type. The mean Euclidean distance between commercial database versus field census locations was 757 and 35 m in the nonurban and urban communities, respectively. However, 94% and 100% of nonurban and urban physical activity facilities, respectively, fell into the same 5-digit ZIP code, dropping to 92% and 98% in the same block group and 71% along the same street. Conclusions: Our findings suggest that the commercial database of physical activity facilities may contain appreciable error, but patterns of error suggest that built environment-health associations are likely biased downward.
KW - Environment Design
KW - Geographic Information Systems
KW - Validation Studies
UR - http://www.scopus.com/inward/record.url?scp=44149104376&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=44149104376&partnerID=8YFLogxK
U2 - 10.1016/j.annepidem.2007.11.008
DO - 10.1016/j.annepidem.2007.11.008
M3 - Article
C2 - 18261922
AN - SCOPUS:44149104376
SN - 1047-2797
VL - 18
SP - 371
EP - 377
JO - Annals of Epidemiology
JF - Annals of Epidemiology
IS - 5
ER -