Should this question be considered off-topic? I have my own opinion which I'll post as an answer.
Is there a measure that uses both cost of living plus income?
I don't know much about economy and financial measures, but was looking at a website that compares cost of living in different countries, but then I realized something was missing. For instance, it would not mean much to me if in India it costs me a third of what I pay here, to buy the same number of coke cans. That would be relevant only if I was paid US salary to live in India.
But what if I am getting paid salary from a source in India? In other words, it may be that in India a research assistant at a college on average earns a third of what a research assistant like me earns here in US. In that case, even if my cost of living there is much less, so is my salary.
So is there a measure that combines these two information? I know it can't be "purchasing power" because that's used more for inflation over time....