Table 2 Example of non-comparability of SMRs
Casemix group | National standard death rate | Hospital A: Death rate | Hospital A: Casemix proportions | Hospital B: Death rate | Hospital B: Casemix proportions |
|---|---|---|---|---|---|
1. High risk | 0.9 | 0.8 | 0.4 | 0.8 | 0.3 |
2. Low risk | 0.1 | 0.2 | 0.6 | 0.2 | 0.7 |
SMR | O = (0.4×0.8) + (0.6×0.2) | O = (0.3×0.8) + (0.7×0.2) | |||
E = (0.4×0.9) + (0.6×0.1) | E = (0.3×0.9) + (0.7×0.1) | ||||
SMR = 105 | SMR = 112 |