# Difference between Confounder, Mediator, Precision Variable, Effect Modifier

While I do have the definitions for each of these 'memorized', I find it hard to actually distinguish between them during the initial steps of confirmatory data analysis.

Example
Looking at how weight affects blood pressure in a longitudinal study. Some hard ones that I am having trouble classifying would be:

Gender
Age
Education Status
Diabetes
Drug Use
Income

What is an easy way that I can tell whether these factors are a Confounder, Mediator, Precision Variable, or Effect Modifier?

• Please add the [self-study] tag & read its wiki. Then tell us what you understand thus far, what you've tried & where you're stuck. We'll provide hints to help you get unstuck. – gung Apr 16 at 16:01