Evaluating the Impact of Diagnostic Modalities Used in Screening for Disease

Evaluation of a diagnostic modality involves 3 questions: Test accuracy/prediction; effect of test on subsequent health care decisions/choices; effect of test on patient outcomes. Assessment of accuracy has received most attention; the impact of a screening test must consider intervening decisions about medical care. I will focus on methodologic challenges in evaluating downstream consequences of a screening test, emphasizing the use of studies with observational data and simulation modeling.