If you wanted to take a pragmatic approach to it, I'd first start by looking at family statistics in the 4-county RGV area. What is average family size (serious question, haven't looked so I don't know)? Then, what are the benefits available to the "average family" in the area, on an annual value basis? Medicaid, CHIP, LoneStar, and other state benefits:
http://www.benefits.gov/benefits/browse-by-state/state/TXWhat Federal handouts does the family qualify for? What are the dollar values of those benefits?
The idea should be to develop a picture of how much in dollar value the "average family" receives annually in government hand-outs and work from there. Average household income is significantly impacted when factoring in these additional monies and without having a handle on that, minimum wage talk is only one-sided. If the "average family" real income includes all the handouts, what is the number? $45K annually? More? Less?