7.8 COMPARING MODELS WITH AND WITHOUT UNEQUAL ERROR COSTS
When we develop Model 2 using R (see the previous section for code details) and evaluate it, we obtain the contingency table shown in Table 7.7.
TABLE 7.7 Contingency table for evaluating Model 2, which incorporates asymmetric error costs
Predicted Category | ||||
0 | 1 | Total | ||
Actual category | 0 | TN = 7163 | FP = 2451 | TAN = 9614 |
1 | FN = 618 | TP = 1322 | TAP = 1940 | |
Total | TPN = 7781 | TPP = 3773 | GT = 11,554 |
Because the error costs for Model 2 are unequal, the evaluative measures introduced earlier are now superseded by a new evaluation measure, model cost per record (or its additive inverse, overall model profit per record).