Most number of false positives by a screening test is becuase of?: (A) High specificity, (B) High sensitivity, (C) High prevalence, (D) Low prevalence
Answer is D. Ref :Parks 23rd edition pg 140. PPV decreases as prevalence decreases. As PPV decreases it means that TP is decreasing. This is accompanied by an increase in FP PPV =TP /(TP +FP)