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Table 1 Built and socioeconomic environment measures:1 data sources and variable descriptions

From: Built and socioeconomic environments: patterning and associations with physical activity in U.S. adolescents

Data source (year); Measure Geographic Area2 Variable description
ESRI StreetMap (2000)   
Street connectivity   
Alpha index3 1 k Ratio of observed to maximum possible route alternatives between nodes (intersections); high values indicate high connectivity.
Beta index3 1 k Ratio of links (connections between nodes) to nodes; high values indicate high connectivity.
Cul de sac density3 1 k Number of cul de sacs (single-link nodes) per square kilometer; low values indicate high connectivity.
Cyclomatic index3 1 k Number of route alternatives between nodes; high values indicate high connectivity.
Gamma index3 1 k Ratio of observed links to the maximum number of links; high values indicate high connectivity.
Intersection density 1 k Number of 3- or more-way intersections (≥links in a single node) per square kilometer
Commercial database of U.S. businesses (1995)
Physical activity facilities   
Instruction (count) 3 k Dance studios, basketball instruction, martial arts
Member (count) 3 k Athletic club and gymnasium, tennis club, basketball club
Outdoor (count) 3 k Sporting and recreation camps, swimming pools
Public (count) 3 k Public beach, pools, tennis courts, recreation centers
Public fee (count) 3 k Physical fitness facilities, bicycle rental, public golf courses
Youth organization (count) 3 k Boy/Girl Scouts, youth centers
ESRI StreetMap Pro, parks component (2003)
Parks (count) 3 k Local parks and recreation areas, classified by Census Bureau classification code
National land cover dataset (1992)   
Landscape diversity   
Mean patch size 1 k Total land patch area divided by the number of patches (square meters)
Patch size variability 1 k Square root of the sum of the squared deviations of each patch area from the mean patch area, divided by the number of patches
Land patch density 1 k Number of land patches per hectare
Simpson's diversity index 1 k Represents the probability that any two pixels selected at random would be different patch types.
Contagion index 1 k Measures texture based on aggregation and interspersion of land patch types
Perimeter-fractal dimension 1 k Measures perimeter and shape complexity
Patch richness3 1 k Number of different patch types (classes)
Mean shape index3 1 k Mean shape index, which measures patch shape and compaction.
Mean fractal dimension index3 1 k Measures perimeter and shape complexity across a range of spatial scales (patch sizes)
U.S. Census (1990)   
Population count 1 k Count of persons within buffer
% below poverty CT Percent of persons living in households with income below the federal poverty level
% minority CT Percent of persons with race/ethnicity other than white non-Hispanic
% college educated CT Percent of persons 25 years and older with at least a college education
Median household income CT Median household income
% homeowners CT Percent of households who own (versus rent) their homes
Uniform Crime Reporting data (1995)
Crime rate Co Number of non-violent and violent crimes per 100,000 population
  1. 1From the National Longitudinal Study of Adolescent Health Obesity Environment Database
  2. 21 k, 3 k = 1 and 3 kilometer Euclidean buffer; CT = census tract; Co = County. Selected neighborhood definitions were selected because they yielded the strongest associations between environment measures and physical activity in previous analysis.
  3. 3Examined in exploratory factor analysis but excluded from final factor solutions based on criteria described in Methods