Question

What is a nested case control study?

What is the difference between a nested case control study and a case control study?

Answer 1

1.A nested case control study can be considered to be a variety of a case control study where the causes and the controls are drawn from the population in a fully enumerated cohort.

The exposure of interest is only measured among the cases, sected controls.

ADVANTAGE:

Thus the nested case control study is more efficient than the full cohort design where this method can be analysed using methods for missing covariates.

2.The basic difference between a case control study and a nested case conycon study is:

The case control study is conceptually based on a cohort.The crucial thing is that contols are chosen independently of exposure which means that the exposed and unexposed controls are the same fraction og the exposed and unexposed source populations.

The nested case control study we get a second selection following the first one.The advantage of a nested case control is to use an already assembled cohort to get more detailed exposure information from a random sample of the non cases at less cost than using all the non cases.