Table 1.
Performance of Different Estimators of the ATT Based on the Disease Risk Score, Derived Using Simulated Data (1,000 Replicated Samples)
| Confounding Status | Effect Modification | Estimator | Bias (×100) | MSE (×100) |
|---|---|---|---|---|
| Weak | No | Naive | −0.5617 | 0.1176 |
| Weak | No | NNM | 0.0046 | 0.1575 |
| Weak | No | OFM | 0.1013 | 0.1419 |
| Weak | No | IPW | −0.0659 | 0.1078 |
| Weak | No | TDW | −0.1076 | 0.1086 |
| Moderate | No | Naive | −1.7546 | 0.1435 |
| Moderate | No | NNM | −0.1308 | 0.1251 |
| Moderate | No | OFM | 0.0130 | 0.1102 |
| Moderate | No | IPW | 0.0313 | 0.0862 |
| Moderate | No | TDW | −0.0968 | 0.0873 |
| Strong | No | Naive | −3.0799 | 0.1994 |
| Strong | No | NNM | −0.1081 | 0.0910 |
| Strong | No | OFM | −0.0664 | 0.0825 |
| Strong | No | IPW | −0.0665 | 0.0688 |
| Strong | No | TDW | 0.0687 | 0.0702 |
| Weak | Yes | Naive | −0.5617 | 0.1250 |
| Weak | Yes | NNM | 0.0301 | 0.1671 |
| Weak | Yes | OFM | 0.1013 | 0.1557 |
| Weak | Yes | IPW | −0.0659 | 0.1159 |
| Weak | Yes | TDW | −0.1076 | 0.1165 |
| Moderate | Yes | Naive | −1.7546 | 0.1487 |
| Moderate | Yes | NNM | −0.1001 | 0.1344 |
| Moderate | Yes | OFM | 0.0130 | 0.1175 |
| Moderate | Yes | IPW | 0.0313 | 0.0953 |
| Moderate | Yes | TDW | −0.0968 | 0.0965 |
| Strong | Yes | Naive | −3.0799 | 0.1986 |
| Strong | Yes | NNM | −0.1496 | 0.0893 |
| Strong | Yes | OFM | −0.0664 | 0.0815 |
| Strong | Yes | IPW | −0.0665 | 0.0701 |
| Strong | Yes | TDW | 0.0687 | 0.0710 |
Abbreviations: ATT, average treatment effect in the treated population; IPW, inverse probability weighting; MSE, mean squared error; NNM, nearest-neighbor matching; OFM, optimal full matching; TDW, target distribution weighting.