The usefulness of a 'screening test' in a community depends on its

Predictive value of a test signifies the diagnostic power of the test.An attribute of an idea screening test is its repeatability or reliability or reproducibility.Sensitivity has been defined as the ability of the test to identify correctly all those who have the disease, that is truly positive (Hence determines the usefulness of the screening test).Specificity is not as impoant. After screening, we can apply a confirmatory test with high specificity.