After poring over the evidence, UCLA's Matthew Kahn concludes that environmentalists practice what they preach.
Should this come as a surprise? When first directed to Kahn's paper, published in the September issue of the Journal of Environmental Economics and Management, I was uncertain why anyone should care. Where I come from, Prius drivers abound, and everybody is nuts about recycling. But that's what one would expect from Berkeley. It seems only natural that environmentalists would make different choices about their consumption patterns than people of different political or philosophical bents.
But it is one thing to know something anecdotally, and it is another to prove it empirically. And in a political environment where the charge of hypocrite is always waiting to be flung (as Al Gore learned all too well), it might be useful to say, well, actually, environmentalists do use less gasoline than "normal" people. There's also the fact, as Kahn notes, that "standard consumption theory focuses on income and relative prices as key determinants of choice." Maybe it's time to give ideology its due, too.
Kahn's methods for investigating his thesis in "Do greens drive Hummers or hybrids? Environmental ideology as a determinant of consumer choice" are interesting in and of themselves, albeit convoluted. He determines whether a given community in California can be considered a hotbed of greenies by looking at the percentage of Green Party registered voters in that community. (California, he observes, has the most Green Party members of any state.) Then he cross-checks that indicator by comparing it to how the community votes on environmentally-themed ballot initiatives in California.
Having established to his satisfaction that census tracts and voting precincts with relatively greater percentages of Green Party members are indeed brimming over with environmentalists, Kahn correlated that information with available data on gasoline consumption, car purchases, access to railway stations, and decided that yes, people who live in those communities are more likely to use public transit and drive hybrid cars. Such communities also feature denser clusters of stores that represent themselves as "green" in those neighborhoods.
But not every hybrid is alike:.
The Toyota Prius' predicted count vastly stands out. The average census tract's Prius predicted count increases from 2.2 to 46.2 as the Green Party share increases from 0 percent to 4 percent. For the other makes, the predicted increase in registration counts is tiny. For example, the Honda Civic Hybrid's predicted count increases from 0.51 to 1.61 when the share of Green Party voters increases. The huge "Prius" effect relative to other almost equally green vehicles suggests that the social interactions effect may dominate the private utility effect from not polluting. Through marketing and celebrity endorsements, the Prius is widely recognized as the "Green Car." Anticipating that their "Greenness" will be acknowledged when they drive this vehicle down their block may encourage households to buy this vehicle.
Seems like it would be cheaper to just ride a bike.
UPDATE: A copy of Kahn's paper can be found here.