Table 3. Confusion matrices associated with random forest and logistic classification models.
| Random forest model | Error ratea | Logistic model | Error ratea | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Colon data set | |||||||||
| Primary data set | Secondary data set | ||||||||
| Predicted | Predicted | ||||||||
| Normal mucosa | Carcinoma | Normal mucosa | Carcinoma | ||||||
| Actual | Normal mucosa | 384 | 29 | Actual | Normal mucosa | 83 | 7 | ||
| Carcinoma | 19 | 561 | Carcinoma | 6 | 104 | ||||
| 4.83% | 6.50% | ||||||||
| Pairs withheld from model fitting | Pairs withheld from model fitting | ||||||||
| Predicted | Predicted | ||||||||
| Normal mucosa | Carcinoma | Normal mucosa | Carcinoma | ||||||
| Actual | Normal mucosa | 389 | 27 | Actual | Normal mucosa | 73 | 5 | ||
| Carcinoma | 10 | 372 | Carcinoma | 3 | 76 | ||||
| 4.64% | 5.10% | ||||||||
| Rectal data set | |||||||||
| Primary data set | Secondary data set | ||||||||
| Predicted | Predicted | ||||||||
| Normal mucosa | Carcinoma | Normal mucosa | Carcinoma | ||||||
| Actual | Normal mucosa | 213 | 6 | Actual | Normal mucosa | 87 | 3 | ||
| Carcinoma | 8 | 333 | Carcinoma | 4 | 106 | ||||
| 2.50% | 3.50% | ||||||||
| Pairs withheld from model fitting | Pairs withheld from model fitting | ||||||||
| Predicted | Predicted | ||||||||
| Normal mucosa | Carcinoma | Normal mucosa | Carcinoma | ||||||
| Actual | Normal mucosa | 211 | 11 | Actual | Normal mucosa | 69 | 2 | ||
| Carcinoma | 4 | 201 | Carcinoma | 3 | 84 | ||||
| 3.51% | 3.16% | ||||||||
OOB, out-of-bag.
a
Error rates for primary data sets are OOB estimates; error rates for secondary data sets are leave-one-out estimates.