Are conservatives happier than liberals?

Arthur Brooks, in a Times op-ed piece, explains that studies conducted on the subject suggest so:

An explanation for the happiness gap more congenial to liberals is that conservatives are simply inattentive to the misery of others. If they recognized the injustice in the world, they wouldn’t be so cheerful. In the words of Jaime Napier and John Jost, New York University psychologists, in the journal Psychological Science, “Liberals may be less happy than conservatives because they are less ideologically prepared to rationalize (or explain away) the degree of inequality in society.” The academic parlance for this is “system justification.”

There's an obvious element of dubiousness here. First of all, how can you actually measure happiness? Happiness seems even more opaque and even harder to quantify than intelligence — and we all know how questionable the tests of 'smartness' are. Brooks ought to focus more on how to devise an accurate measure for this abstract concept. At the moment, we're dependent on how happy people think they are. And although it might sound silly to you, I'm not really sure I trust their judgement.

Ann Althouse — now here's someone whose judgement we can't trust — takes a guess: "[Conservatives] mind their own business. They think taking care of their own work and family is enough, and liberals feel they must worry about how everyone else is doing." Sure. Whatever. On a related note, if you haven't read Oscar Wilde's essay, "The Soul of Man Under Socialism", you really must.