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Confusion matrix

A table comparing reference classes with model predictions and counting correct and incorrect assignments.

Machine learning

Which confusions does the table show?

A confusion matrix compares reference classes with model predictions. Here, rows contain cases assigned under a defined business rule and columns contain the model prediction. The fictional example covers 50 service requests; the positive class is intended for technical service. The orientation and class labels must be clear, because the same numbers can otherwise be interpreted incorrectly.

Reference class

Model: technical service

Model: other request

Technical service

18

2

Other request

6

24

The 18 cases at the top left are true positives. The 2 at the top right were missed, the 6 at the bottom left were incorrectly marked positive, and the 24 at the bottom right were correctly identified as other requests. The table thus separates requests that fail to reach the technical team from extra requests wrongly sent there. It can be extended to further classes. Its meaning also depends on the quality of the reference assignments and how well the selected examples cover the intended use.

Sources