Asked about When one class is rare

Your classes are 99 to 1. What do you do?

An answer that works

Stop using accuracy, and use precision, recall and PR AUC. Try class weights first, tune the decision threshold from the precision-recall curve rather than leaving it at 0.5, and evaluate on the real distribution rather than a rebalanced one.

Reading an answer is not being able to give one. The section that teaches this is When one class is rare, 5 hours of Imbalanced and messy data.

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