Labor income or household income

I am working on a study attempting to estimate the tax impact of increased worker income. Specifically, what are the tax impacts if a group of underpaid workers were compensated at the same rate as the rest of the "market." We've calculated an estimated wage gap between these two groups of workers. 

To get the best estimate of potential tax impacts, should I set up my activity as a "labor income change" or as a "household income change?"

Thank you.