From: Purposeful selection of variables in logistic regression
Confounding | Non-candidate Inclusion | n | Purposeful | Stepwise | Backward | Forward |
---|---|---|---|---|---|---|
20 | 0.1 | 60 | 5 | 3.6 | 6.3 | 9.1 |
 |  | 120 | 17.3 | 15.6 | 18.2 | 18.8 |
 |  | 240 | 39.7 | 39.6 | 40.1 | 30.3 |
 |  | 360 | 55.2 | 54.4 | 54.4 | 36.6 |
 |  | 480 | 64.3 | 64.3 | 64.3 | 37.5 |
 |  | 600 | 65.8 | 65.7 | 65.7 | 41.3 |
20 | 0.15 | 60 | 9.2 | 4.6 | 6.4 | 8.1 |
 |  | 120 | 18.7 | 14.8 | 17.2 | 18.5 |
 |  | 240 | 43.1 | 37.1 | 38.2 | 30.5 |
 |  | 360 | 56.5 | 53.7 | 53.9 | 37 |
 |  | 480 | 63.6 | 62.6 | 62 | 43 |
 |  | 600 | 70.3 | 69 | 68.7 | 41 |
15 | 0.1 | 60 | 6.6 | 4.1 | 6.1 | 9.6 |
 |  | 120 | 17.8 | 15.6 | 18.6 | 19.2 |
 |  | 240 | 39.7 | 36.6 | 37.6 | 29.8 |
 |  | 360 | 53.3 | 52.2 | 52.6 | 38.3 |
 |  | 480 | 62.4 | 62.1 | 62.1 | 40.1 |
 |  | 600 | 68.5 | 67.9 | 68 | 40.2 |
15 | 0.15 | 60 | 9.7 | 4.4 | 6.7 | 9 |
 |  | 120 | 21.9 | 16.8 | 21.3 | 19.6 |
 |  | 240 | 46.6 | 40.2 | 41.4 | 32.3 |
 |  | 360 | 57.7 | 52.5 | 52.5 | 35.3 |
 |  | 480 | 64 | 63.1 | 63.1 | 39.3 |
 |  | 600 | 70.4 | 69.6 | 69.6 | 41.4 |