The false positive (FP), together with false negative (FN) (*), is a type of inaccurately predicted outcome, meaning that the prediction does not match the true observation/ condition in terms of the class (positive/ negative).

FP occurs when a positive class prediction (classification) was inaccurately made when a negative class prediction, when accurately predicted, should have been made.

In the example of the mammogram: If the woman who is tested positive for breast cancer does not actually have the disease, such an incorrect prediction is called FP.