Table 3.
Sample size and number of candidate predictors informing analyses for 152 developed models, by modelling type
| Regression-based models (n = 42) | Non-regression-based models (n = 71) | Ensemble models (n = 39) | ||||
|---|---|---|---|---|---|---|
| Reported, n (%) | Median [IQR], range | Reported, n (%) | Median [IQR], range | Reported, n (%) | Median [IQR], range | |
| Total sample size | ||||||
| Model development | 42 (100) | 561 [203 to 2822], 20 to 582,398 | 70 (99) | 447 [156 to 11,901], 20 to 582,398 | 39 (100) | 768 [203 to 1599], 20 to 582,398 |
| Internal validationa | 20 (48) | 122 [82 to 228], 47 to 291,200 | 35 (49) | 145 [90 to 492], 47 to 291,200 | 24 (62) | 162 [97 to 1510], 67 to 291,200 |
| External validation | 12 (29) | 511 [67 to 2300], 11 to 836,659 | 14 (20) | 793 [59 to 1675], 11 to 836,659 | 11 (28) | 313 [229 to 836,659], 11 to 836,659 |
| Number of events | ||||||
| Model development | 20 (48) | 236 [34 to 1326], 7 to 35,019 | 37 (52) | 62 [22 to 1075], 7 to 45,797 | 10 (26) | 37 [22 to 241], 8 to 35,019 |
| Internal validationa | 2 (5) | 41 [21 to 61], 21 to 61 | 3 (4) | 61 [21 to 62], 21 to 62 | 1 (3) | 61 |
| External validation | 8 (19) | 81 [18 to 327], 7 to 513 | 11 (15) | 19 [7 to 513], 7 to 1323 | 5 (13) | 81 [81 to 81], 7 to 513 |
| No. candidate predictors | 38 (90) | 21 [15 to 34], 6 to 33,788 | 64 (90) | 16 [12 to 25], 5 to 33,788 | 36 (92) | 25 [14 to 37], 4 to 33,788 |
| Events per predictorb | 20 (48) | 8.0 [7.1 to 23.5], 0.2 to 5836.5 | 35 (49) | 3.4 [1.1 to 19.1], 0.2 to 5836.5 | 10 (26) | 1.7 [1.1 to 6.0], 0.7 to 5836.5 |
aCombines all internal validation methods, e.g., split sample, cross validation, bootstrapping
bEvents per predictor for model development