Roverbially, money buys neither love nor happiness, only sex. ("Success in the boardroom guarantees success in the bedroom.") But nobody ever tried to prove it.
Recently, however, two economists, David G. Blanchflower of Dartmouth College and Andrew J. Oswald of the University of Warwick in England, submitted a working paper called "Money, Sex and Happiness: An Empirical Study," to the National Bureau of Economic Research, one of the leading organizations in its field.
The authors say their study is first rigorous econometric analysis on the topic, and it that the received wisdom may require some revision. As the paper states: "Money does seem to seem to buy greater happiness. But it does not buy more sex."
Mr. Blanchflower and Mr. Oswald are among the leaders in the fast-growing field of "happiness economics," which applies econometric techniques, traditionally limited to quantifiable matters like wage rates, to the amorphous arena of human emotion. Areas of research include how happiness is affected by democracy (it increases individual happiness), or new cigarette taxes (smokers, oddly, become happier).
In their study, Mr. Oswald and Mr. Blanchflower analyzed the self-reported sexual activity and levels of happiness of more than 16,000 American adults who participated in a number of social surveys since the early 1990's. (Happiness is notoriously difficult to define, and the surveys make no attempt to do so; the respondents simply record how happy they believe themselves to be on a sliding scale.) By factoring out the measurable effects of other life events, the study revealed, to no one's surprise, that, "The more sex, the happier the person."
Furthermore, the economists compared the levels of happiness produced by a vigorous sex life with other activities whose economic values had been calculated in prior research, allowing them to impute, in dollars, how much happiness sex was worth. They also estimated that increasing the frequency of sexual intercourse from once a month to at least once a week provided as much happiness as putting $50,000 in the bank.
A lasting marriage, by comparison, offers about $100,000 worth of happiness a year - that is, on average, a single person would need to receive $100,000 annually to be as happy as a married person with the same education, job status and other characteristics. Divorce, on the other hand, imposes an emotional toll of about $66,000 a year, though there may be a short-term economic gain from the immediate relief provided by leaving your spouse.
Possibly the least expected finding of the paper, said Mr. Oswald, was that in general, "Greater income does not buy more sex, nor sexual partners."
"That was surprising to us as economists," Mr. Oswald added, "because by and large, we think money can buy anything." (The study found that men who paid a prostitute for sex reported they were considerably less happy.)
But the economists' study struck at a number of conventionally accepted notions. "The conservative, pro-marriage lobby will be delighted to read our paper," Mr. Oswald said. "The 'Sex and the City' view of the world is falsified by the data."
Married people, he said, were shown to have about 30 percent more sex than their single peers, and were found, at least statistically speaking, to be significantly happier.
Likewise, Mr. Oswald said, the gay and lesbian community would be happy with the work. The data showed that the amount of happiness obtained from "being in a gay relationship is almost identical to being in a heterosexual one" and that regardless of sexual orientation, the "happiness-maximizing" number of partners is one. Celibacy and very low levels of sexual activity, the study found, had a "statistically indistinguishable" effect on happiness.
Not everyone is convinced one can put an accurate price tag on sex - or at least its emotional payoff. "Does it matter if it is good sex or bad sex? To me that is of critical importance," said Leonore Tiefer, a clinical therapist and associate professor of psychiatry at the New York University School of Medicine.
Then there is the problem of distinguishing cause from effect. "Is your sex life good because you are seeing life through rose-colored glasses?" asked Edward O. Laumann, a University of Chicago sociology professor who directed the 1994 National Health and Social Life Survey, a landmark study on sexual attitudes and behaviors in the United States. "Or is your happiness a result of your sex life?" And what about the lurking variable of love?
Mr. Oswald concedes the limitations of his statistical analysis. "All we can do is paint outlines of the numbers," he said. "We can't hope to pick up a myriad of details." However, he said a statistical approach can be useful in flushing out evidence that would be difficult to otherwise obtain - especially when it comes to a topic like sex, where there is a strong incentive to lie.
He said he would like to carry out more highly detailed, longitudinal and cross-culture studies, but behavioral lab experiments remain out of the question now. "It would be great to assign Mr. and Mrs. X a certain amount of sexual activity and a certain amount of income, and see how it impacts their happiness," he said. "But I think it would be hard to get government funding."