<prompt> If the prevalence of a disease in a population increases, the predictive value of a positive test -DecreasesIncreasesRemains constantBecomes compromised  <response>: Effect of prevalence on positive predictive value -As prevalence of disease increases in a population, PPV of screening test increases.It is easy to understand, if the number of patients increases in a population the probability of a positive test will also increases.See following examples 