Table 2.
Buffer Radius (m) | Number of children within buffer zone | Comparison measures | |||||||
Parcels | Street | Parcels yes/Street yes | Parcels yes/Street no | Parcel no/Street yes | Parcel no/Street no | Sensitivity (%)1 | Specificity (%)2 | Odds Ratio (95% CI)3 | |
50 meters | 391 | 1413 | 151 | 240 | 1262 | 103212 | 39 | 99 | 0.28 (0.25 – 0.31) |
100 meters | 2090 | 2851 | 1392 | 698 | 1459 | 101316 | 67 | 99 | 0.73 (0.69 – 0.77) |
150 meters | 4717 | 5276 | 3899 | 818 | 1377 | 98771 | 83 | 99 | 0.89 (0.85 – 0.93) |
250 meters | 10729 | 10945 | 9704 | 1025 | 1241 | 92895 | 90 | 99 | 0.98 (0.95 – 1.01) |
500 meters | 26347 | 26597 | 25201 | 1146 | 1396 | 77122 | 96 | 98 | 0.99 (0.97 – 1.01) |
1000 meters | 54500 | 54614 | 53838 | 662 | 776 | 49589 | 99 | 98 | 01.00 (0.980 – 1.01) |
1 Sensitivity is the percentage of parcel geocoded children residing within the buffer zone that were correctly classified using street geocoding.
2 Specificity is the percentage of parcel geocoded children residing outside the buffer zone that were correctly classified using street geocoding.
3 The odds-ratio is determined by comparing the parcel and street geocoded populations. The odds-ratio represents the odds that parcel geocoded addreses are within a given buffer radius, given that street-geocoded locations for the same address fall inside vs. outside the buffer radius. A value less than 1 indicates that the odds for the parcel geocoded population residing within the buffer radius is lower than for the street geocoded population