to identify confounders, there might be several ways

 

1. business related

2. there is some sort of association between outcomes/predictor and the variable.

- if both are continuous vars, correlation works

- if both are categorical vars, chi square test works

- if one categorical one continuous vars, t test works

3. toss all those vars that are business relevant or with some kind of assoication with outcomes/predictors into a model, such as linear, logistic, or some other regression which might be detemined by the industry/business, and then determine if the difference is still statistical signficant. We can tell that by checking the p-Value assoicated with that specifc regression coefficient.