Freitag, 30. Mai 2014

Utility vs. Welfare

Nicht das gleiche.

Ein interessanter Beitrag über "die Makrofundierung der Mikroökonomik" hat eine Serie über den Unterschied zwischen Utility und Welfare auf dem Blog interfluidity gestartet.

Es geht im Kern darum, dass man Nutzen a) nur schwer kardinal messen kann und b) eigentlich überhaupt nicht interpersonal vergleichen kann.
"Let’s consider another common case [...]. Suppose there is a limited, inelastic supply of road-lanes flowing onto the island of Manhattan. If access to roads is ungated, unpleasant evidence of shortage emerges. Thousands of people lose time in snarling, smoking, traffic jams. A frequently proposed solution to this problem is “congestion pricing”. Access to the bridges and tunnels crossing onto the island might be tolled, and the cost of the toll could be made to rise to the point where the number of vehicles willing to pay the price of entry was no more than what the lanes can fluidly accommodate.

The case for price-rationing of an inelastically supplied good is very strong under two assumptions: 1) that people have diverse needs and preferences related to the individual circumstances of their lives; and 2) willingness to pay is a good measure of the relative strength of those needs and values. Under these assumptions, the virtue of congestion pricing is clear. People who most need to make the trip into Manhattan quickly, those who most value a quick journey, will pay for it. Those who don’t really need the trip or don’t mind waiting will skip the journey, or delay it until the price of the journey is cheap. When willingness to pay is a good measure of contribution to welfare, price rationing ensures that those more willing to pay travel in preference to those less willing, maximizing welfare.

Unfortunately, willingness to pay cannot be taken as a reasonable proxy for contribution to welfare if similar individuals face the choice with very different endowments. Congestion pricing is a reasonable candidate for near-optimal policy in a world where consumers are roughly equal in wealth and income. The more unequal the population of consumers, the weaker the case for price rationing. Schemes like congestion pricing become impossibly dumb in a world where a poor person might be rationed out of a life-saving trip to the hospital by a millionaire on a joy ride. Your position on whether congestion pricing of roads, or many analogous price-rationing schemes, would be good policy in practice has to be conditioned on an evaluation of just how unequal a world you think we live in."
Und hier noch der Link zum Nachfolgebeitrag.

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