Table 2.
Comparison of continuous features between the training and validation sets
| Feature | Training set (n = 189) | Validation set (n = 815) | % Missing data from validation set | P | |
|---|---|---|---|---|---|
| Age at surgery (years)‡ |
Mean |
62.4 |
66.3 |
0 |
0.0002* |
| SD |
13.7 |
12.8 |
|||
| Median |
62.7 |
67.0 |
|||
| IQR |
54.4, 72.2 |
58.0, 76.0 |
|||
| Hemoglobin concentration (mg/dL)†‡ |
Mean |
11.5 |
11.5 |
0.6 |
1.0 |
| SD |
1.9 |
3.5 |
|||
| Median |
11.4 |
11.3 |
|||
| IQR |
10.1, 12.9 |
10.3, 12.6 |
|||
| Absolute lymphocyte count (K/μL)†‡ |
Mean |
1.2 |
1.2 |
83.8 |
0.48 |
| SD |
1.3 |
0.74 |
|||
| Median |
1.0 |
1.2 |
|||
| IQR |
0.6, 1.5 |
0.8, 1.6 |
|||
| Senior surgeon’s estimate of survival (months)†‡ |
Mean |
10.3 |
N/A | 100 | N/A |
| SD |
8.6 |
||||
| Median |
6.0 |
||||
| IQR | 4.0, 12.0 | ||||
SD=standard deviation; IQR=interquartile range; N/A=not applicable.
*Distributions are significantly different between training and validation sets by two-tailed Student’s t-test.
†Denotes feature of 3-month model.
‡Denotes feature of 12-month model.