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arXiv · 2007.01905

The Effect of Class Imbalance on Precision-Recall Curves

Christopher K I Williams
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Abstract

In this note I study how the precision of a classifier depends on the ratio $r$ of positive to negative cases in the test set, as well as the classifier's true and false positive rates. This relationship allows prediction of how the precision-recall curve will change with $r$, which seems not to be well known. It also allows prediction of how $F_{\beta}$ and the Precision Gain and Recall Gain measures of Flach and Kull (2015) vary with $r$.

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Christopher K I Williams. 2020-07-03. The Effect of Class Imbalance on Precision-Recall Curves. https://doi.org/10.1162/neco_a_01362

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