Question

List three criteria for determining causality in epidemiology. Give examples for each.

Answer 1

Criteria for detecting causality in epidemiology

Three criteria

1)association

2) time order

3) nonspuriousness

Association - first criteria for detecting causality is association sometimes called correlation between independent and dependent variables. They must vary together when one goes up (or down) ,other goes up (or down ) at same time. For example -- when cigratte smoking goes up, so does the lung cancer. Longer you stay in school, more money you are going to get later in your life. In these example

change in independent variables correlates with change in dependent variables. So association is most important ways to detect causality.

Time order - association is necessary, but not sufficient, We must also ensure that variation in independent variable came before variation in dependent variable. The cause must come before its presumed effect.This is the criteria of time order. Or the temporal variety of independent variable

Nonspuriousness - third criteria for detecting causality is nonspuriousness. Spurious means false or not genuine. Cause of casulity should be genuine. Casulity should be genuine or involves large number of people.