What are covariate and cofounder variables

Question

I need help finding the covariate and cofounder variables in the research paper i am looking at, or help learning how to find it, I have researched and tried to figure out what a cofounder and covariate is and I can't seem to gasp the concept.

Research article below

https://pdfs.semanticscholar.org/f721/83752466bc437769a310c2c868e320ec217f.pdf?_ga=2.63084271.1577620017.1564157608-207581357.1564157608

Answer 1

A covariate variable is one that can affect an outcome variable, but is not one you are interested in including with your model at this time.

A straightforward example might be

You are interested in building a model where the outcome (dependent) variable is salary, and you want to use no of years experience and gender as your explanatory variables. You recognize that age might affect salary, but you don't want to include it (for whatever reason) among your explanatory vabiables in your model. But, it could be a covariate

Hope this helps

Prof Charlie