Introduction to Epidemiology 6th Edition by Ray M Merrill

Exercise 1

Why is random assignment in a clinical trial an effective way to avoid confounding?

Step 1 of 3

Medical screening is used for detection of diseases in a population with no signs and symptoms of health problems. It is intended to identify a disease as early as possible so as to reduce mortality from the disease. A chronic disease may be caused by more than one factor, all of which may produce similar disease outcomes.

Prognosis of a disease means to identify the likely outcomes of a disease based on the presence of signs and symptoms in a population. Improper prognosis or errors during prognosis can result in bias of the actual data/result. Bias is a systematic error in the epidemiological study which results in the incorrect estimate of association between risk of disease and exposure.