Table 7.
Sensitivity and positive predictive value (PPV) of the flexible and cylindrical space-time scan statistics.
| zip codes | population | |||||
| traditional power | sensitivity (%) | PPV (%) | sensitivity (%) | PPV (%) | ||
| Cluster A; s* = 1; high risk | ||||||
| Day 31 | flexible (K = 20) | |||||
| cylindrical (K = 20) | 0.860 | 85.30 | 89.45 | 85.30 | 91.50 | |
| cylindrical (50% pop) | 0.862 | 85.90 | 88.79 | 85.90 | 90.84 | |
| Day 32 | flexible (K = 20) | 0.988 | 98.80 | 84.50 | 98.80 | 87.80 |
| cylindrical (K = 20) | 0.996 | 99.50 | 97.44 | 99.50 | 98.18 | |
| cylindrical (50% pop) | 0.996 | 99.50 | 97.33 | 99.50 | 98.08 | |
| Day 33 | flexible (K = 20) | 0.999 | 99.90 | 96.27 | 99.90 | 97.32 |
| cylindrical (K = 20) | 0.999 | 99.90 | 99.48 | 99.90 | 99.65 | |
| cylindrical (50% pop) | 0.999 | 99.90 | 99.48 | 99.90 | 99.65 | |
| Cluster A5; s* = 5; high risk | ||||||
| Day 31 | flexible (K = 20) | 0.797 | 66.08 | 55.93 | 67.29 | 63.00 |
| cylindrical (K = 20) | 0.850 | 69.62 | 80.35 | 71.65 | 84.21 | |
| cylindrical (50% pop) | 0.847 | 70.62 | 78.17 | 71.62 | 82.02 | |
| Day 32 | flexible (K = 20) | 0.994 | 92.22 | 70.17 | 92.94 | 76.73 |
| cylindrical (K = 20) | 0.996 | 88.78 | 85.14 | 90.86 | 89.41 | |
| cylindrical (50% pop) | 0.996 | 88.96 | 84.81 | 91.05 | 89.11 | |
| Day 33 | flexible (K = 20) | 1.000 | 95.88 | 80.02 | 96.64 | 85.25 |
| cylindrical (K = 20) | 1.000 | 91.42 | 87.32 | 93.66 | 91.67 | |
| cylindrical (50% pop) | 1.000 | 91.42 | 87.30 | 93.66 | 91.65 | |
| The Rockaways; s* = 5; high risk | ||||||
| Day 31 | flexible (K = 20) | 0.769 | 60.68 | 72.09 | 69.04 | 73.58 |
| cylindrical (K = 20) | 0.855 | 62.32 | 91.63 | 74.45 | 91.76 | |
| cylindrical (50% pop) | 0.840 | 61.40 | 91.04 | 73.65 | 91.15 | |
| Day 32 | flexible (K = 20) | 0.992 | 86.76 | 87.36 | 94.17 | 89.86 |
| cylindrical (K = 20) | 0.997 | 77.00 | 96.84 | 92.75 | 97.46 | |
| cylindrical (50% pop) | 0.997 | 77.00 | 96.84 | 92.75 | 97.46 | |
| Day 33 | flexible (K = 20) | 1.000 | 92.16 | 93.81 | 97.15 | 95.97 |
| cylindrical (K = 20) | 1.000 | 78.50 | 98.06 | 94.51 | 98.59 | |
| cylindrical (50% pop) | 1.000 | 78.50 | 98.06 | 94.51 | 98.59 | |
| Hudson River, s* = 20; high risk | ||||||
| Day 31 | flexible (K = 20) | 0.656 | 20.07 | 64.99 | 26.00 | 69.72 |
| cylindrical (K = 20) | 0.597 | 14.23 | 61.10 | 18.16 | 65.18 | |
| cylindrical (50% pop) | 0.632 | 26.15 | 50.70 | 31.26 | 53.71 | |
| Day 32 | flexible (K = 20) | 0.964 | 32.17 | 73.59 | 41.81 | 78.36 |
| cylindrical (K = 20) | 0.933 | 24.13 | 61.55 | 31.58 | 66.69 | |
| cylindrical (50% pop) | 0.949 | 42.90 | 50.27 | 51.50 | 53.96 | |
| Day 33 | flexible (K = 20) | 0.998 | 34.91 | 79.39 | 46.27 | 84.17 |
| cylindrical (K = 20) | 0.994 | 27.23 | 60.56 | 36.75 | 66.20 | |
| cylindrical (50% pop) | 0.995 | 48.14 | 47.34 | 58.54 | 51.34 | |