“Under marginalist economics, any production input with a price has ‘marginal productivity’ equal to what it adds to the final price of the good. So under that orthodox paradigm, the toll-gate owners would have ‘marginal productivity’ equal to whatever cost the toll added to total production costs and prices, and economists would be stroking their beards and intoning learnedly about the ’service’ the toll collectors perform in not impeding traffic on the roads. And of course, GDP would increase by the amount of the tolls. In other words, anything anyone can do to make it more costly to produce anything, to increase the amount of money you have to pay to receive a given good or service, or in general to increase the cost of living our daily lives, will show up as an increase in the GDP.” (03/12/10)