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Precision

The share of actually positive cases among all cases the model marks as positive.

Machine learning

How reliable is the positive label?

Precision measures what share of positively labelled cases are actually positive according to the defined reference. The formula is TP / (TP + FP): TP means true-positive and FP false-positive assignments. The metric belongs to the selected class and assessment. If no case was labelled positive, the denominator is zero; reporting must make the handling of such an undefined value clear.

In a fictional calculation with 50 service requests, a model marks 24 as belonging to technical service. Under the previously agreed assignment rule, 18 actually belong there and 6 are incorrectly marked. Precision is 18 / 24 = 75 %. For operations, this view makes the additional misrouted cases visible. The metric alone does not show whether technical requests were also missed; recall is examined for that purpose.

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