Table 1 The social, housing and environmental variables considered. All factors were summarized at the census tract level for the two county study area.
Variable | Description | Mean for all 1481 tracts in the study area |
|---|---|---|
Population density | Housing units per square kilometer | 2.02 units/square kilometer |
Income | Median household income | $48,031 |
Race | Percentage of population that is white | 54% |
Age | Median age of population | 33.7 years |
Elevation | Mean elevation | 192 meters above MSL |
| Â | Elevation range | 9.0 meters |
Vegetation | Percentage vegetated | 21.3% |
Positive bird specimens | Meters from nearest positive bird | 1965 meters |
Housing age | Percentage of housing built 1940–1949 | 11.8% |
|  | Percentage of housing built 1950–1959 | 18.0% |
|  | Percentage of housing built 1940–1959 | 29.8% |
Physiographic region | In the Chicago Lake Plain region or outside | Dummy variable |
Mosquito Abatement District (MAD) status | In one of four MADs, DuPage County or outside of those areas | Dummy variables |