Table 1.
Results comparing the performance of the binary methods in four samples of 5,000 addresses each from Fife and Tayside
| NHS Fife Population 213 (4.3%) true care-home addresses Estimate % (95% CI) | NHS Tayside Population 253 (5.1%) true care-home addresses Estimate % (95% CI) | NHS Fife ≥65-year-olds 556 (11.1%) true care-home addresses Estimate % (95% CI) | NHS Tayside ≥65-year-olds 431 (8.6%) true care-home addresses Estimate % (95% CI) | |
|---|---|---|---|---|
| CHI Institution Flag | 121 Identified as care-home | 154 Identified as care-home | 327 Identified as care-home | 394 Identified as care-home |
| Sensitivity | 55.8% (48.9–62.5) | 59.7% (53.3–65.7) | 58.6% (54.4–62.7) | 89.3% (85.9–92.0) |
| Specificity | 99.9% (99.8–99.9) | 99.9% (99.7–99.9) | 99.9% (99.8–99.9) | 99.8% (99.6–99.9) |
| Positive predictive value | 99.2% (94.8–99.9) | 98.1% (93.9–99.5) | 99.6% (98.0–99.9) | 97.7% (95.6–98.9) |
| Negative Predictive value | 98.1% (97.6–98.4) | 97.9% (97.4–98.3) | 95.1% (94.4–95.7) | 99.0% (98.7–99.3) |
| Exact address match | 0 Identified as care-home | 0 Identified as care-home | 0 Identified as care-home | 0 Identified as care-home |
| Sensitivity | 0.0% (0.0–2.2) | 0.0% (0.0–1.9) | 0.0% (0.0–0.1) | 0.0% (0.0–1.1) |
| Specificity | 100.0% (99.9–100.0) | 100% (99.9–100.0) | 100% (99.9–100.0) | 100% (99.9–100) |
| Positive predictive value | – | – | – | – |
| Negative Predictive value | 95.7% (95.1–96.3) | 94.9% (94.3–95.5) | 88.9% (87.9–89.7) | 91.4% (90.5–92.1) |
| Postcode match | 251 Identified as care-home | 252 Identified as care-home | 580 Identified as care-home | 454 Identified as care-home |
| Sensitivity | 90.2% (85.3–93.7) | 78.2% (72.6–83.1) | 89.2% (86.3–91.6) | 89.6% (78.6–94.4) |
| Specificity | 98.8% (98.4–99.1) | 98.9% (98.5–99.1) | 98.1% (97.7–98.5) | 98.5% (98.1–98.8) |
| Positive predictive value | 77.3% (71.5–82.2) | 78.6% (72.9–83.4) | 85.5% (82.3–88.2) | 85.0% (81.3–88.1) |
| Negative Predictive value | 99.6% (99.3–99.7) | 98.8% (98.5–99.1) | 98.6% (98.2–98.9) | 99.0% (98.7–99.3) |
CHI, Community Health Index; Negative predictive value—the proportion of addresses identified as non-care-home addresses which are not care-homes; Positive predictive value—the proportion of addresses identified as care-homes which are care-home addresses; Sensitivity—the proportion of care-home addresses correctly identified by each method; Specificity—the proportion of non-care-home addresses correctly identified by each method.