Actually I just tried to tease out a definition from the investopedia article, which I was mislead reading the sales tax example which has a fixed amount (the p

Actually I just tried to tease out a definition from the investopedia article, which I was mislead reading the sales tax example which has a fixed amount (the price of some taxable goods) which holds no sliding scale based on income. The regression appears to be strictly around the idea of burden to the individual and how much disposable income they get left with. Looking at the wikipedia article they claim that flat tax lies between a regressive and progressive tax. > The opposite of a regressive tax is a progressive tax, in which the average tax rate increases as the amount subject to taxation rises. In between is a flat or proportional tax, where the tax rate is fixed as the amount subject to taxation increases. https://en.wikipedia.org/wiki/Regressive_tax https://en.wikipedia.org/wiki/Regressive_tax Where in my statement does the assumption of equal income mobility pop up? Another hit mentions a proportional tax as a middle ground between regressive and progressive gradients. The central point is how things are treated relative to income. https://www.investopedia.com/ask/answers/042415/what-are-differences-between-regressive-proportional-and-progressive-taxes.asp https://www.investopedia.com/ask/answers/042415/what-are-dif...