Table 1.
Summary of some characteristics of VIMs
| Methods | GVIM | PVIM (CART-RF) | PVIM (CIT-RF) | CPVIM | varSelRF | varSelMD | IPM |
|---|---|---|---|---|---|---|---|
| Main references | [43] | [2] | [13, 15] | [25] | [26] | [10, 33] | [11] and this manuscript |
| Key characteristic | Node impurity | Accuracy after variable permutation | Accuracy after variable permutation | Alternative of PVIM; Conditional permutation | Backward elimination | Variable selection based on MD | Variables intervening in prediction |
| RF-based | CART-RF | CART-RF | CIT-RF | CIT-RF | CART-RF | CART-RF | CART-RF or CIT-RF |
| Handling of response | Univariate | Univariate | Univariate | Univariate | Categorical | All (multivariate included) | All (multivariate included) |
| Main R implementation | randomForest [18, 19] | randomForest [18, 19] randomForestSRC [20–22] | party [23–25] | party [23–25] | varSelRF [27, 28] | randomForestSRC [20–22] | Additional file 2 |
| Casewise importance | No | Yes | Not defined | Not defined | No | No | Yes |