In the Darwinian world of high-school dating, freshman girls and senior boys have the highest chances of successfully partnering up. Senior girls (too picky!) and freshman boys (pond scum!) have the least.

These are truisms known to anyone who has watched 10 minutes of a teen movie or spent 10 minutes in a high school cafeteria. Now, however, social scientists have examined them exhaustively and empirically. And they have found that for the most part, they’re accurate. So are some other old prom-era chestnuts: Teen boys are primarily—obsessively?—interested in sex, whereas girls, no matter how boy-crazy, tend to focus on relationships. Young men frequently fib about their sexual experience, whereas young women tend to be more truthful. Once a student has sex, it becomes less of an issue in future relationships.

A recently released paper—called “ Terms of Endearment ,” but don’t hold its too-cute title against it—looked at how and when high-school students choose mates and their preferences when searching for a partner. Economists Peter Arcidiacono and Marjorie McElroy of Duke and Andrew Beauchamp of Boston College examined an enormous trove of data from the National Longitudinal Study of Adolescent Health, more commonly known as Add Health . The survey first queried adolescents, from seventh graders to high-school seniors, during the 1994-1995 school year and has followed up with them periodically.

The poll asked a broad range of questions about health and behavior—and the data set has become the basis of dozens of famed medical, sociological, and economic studies. (For instance, James Fowler of UC-San Diego recently used data from Add Health to find that there might be a genetic foundation for an individual’s political beliefs.) For their paper, Arcidiacono, McElroy, and Beauchamp focused on the dating and sex lives of high schoolers—a subject much-analyzed by magazine editors and romantic-comedy screenwriters, but less familiar to social scientists.

What the researchers looked for is called, in academic-speak, “matching”: the likelihood and factors that lead to any individual partnering up. (They looked only at opposite-sex relationships within the same school.) That’s uncommon: Most academic studies on marriage and partner-matching use a technique called “ assortative mating ,” which looks at pre-existing couples and defines the characteristics they do and do not have in common. (Humans tend to partner with mates that look and act like them. In real terms, that means couples with the same socioeconomic, racial, and religious background are common. In high-school terms, that means math nerds date math nerds, though members of the debate team may also qualify.)

Arcidiacono, McElroy, and Beauchamp used a “ two-sided matching model ,” which looks at what an individual says he or she seeks in a partner as well as what he or she ends up getting. The idea is that men and women—jocks and dorks, freshman and seniors—base their search not only on the characteristics of their chosen partner, but also the expected terms of the relationship. For 30-year-olds, that might mean predicating a relationship on willingness to marry or have kids. For high schoolers, that might mean basing a relationship on, well, the bases .

Arcidiacono notes that there’s a treasure trove of statistical data on the dating preferences, rather than pairings, of adults, due to dating sites like Match.com. Relatively little such data exists for teenagers, who mostly work the old-fashioned meet-someone-in-homeroom way. But in examining the Add Health data, he and his colleagues found one classic economic tenet driving the byzantine high-school dating market: Scarcity determines value. Among freshman boys, what’s rare, and therefore valuable, are freshman girls willing to have a relationship and, even better, willing to have sex. Among senior girls, what’s valuable and scarce are boys willing to have a relationship without having sex.

The researchers open the paper by citing a New York Times article on dating at the University of North Carolina, where for every three women there are only two men. One coed argues that the gender imbalance has engendered a culture where men routinely cheat on their female partners. “That’s a thing that girls let slide, because you have to,” the student explains. “If you don’t let it slide, you don’t have a boyfriend.” Dating, in other words, is a market like any other, and market power is determined by the abundance of resources.

A tamer version of that observation is borne out in the economists’ work among high schoolers. Unsurprisingly, the majority of high school boys want to have sex (though only 47.6 percent of freshmen boys do). Unsurprisingly, the majority of high school girls do not (though 50.1 percent of senior girls do). Over the course of four years, the power shifts from the freshman girls who don’t want to have sex to the senior boys who do.

The conclusion? Though high-school girls don’t really want to have sex, many more of them end up doing so in order to “match” with a high-school boy. For them, a relationship at some point becomes more important than purity. Because of that phenomenon, in schools with more boys than girls, the girls hold more cards and have less sex. Where there are more girls, the male preference for sex tends to win out.

Of course, all this raises a question that has long bedeviled scores of Y.A. novelists, not to mention millions of teenagers: In high school, how exactly does one define a “relationship”? Rather sweetly, the Add Health study considers two a pair when they hold hands, kiss, and say “I love you.” (It seems to me this knocks most high-school relationships out of consideration, but the criteria are the criteria.) And when does that happen? Boys and girls in the same grade account for about 42 percent of relationships, while older boys dating younger girls make up 40 percent of high-school relationships, and older girls dating younger boys make up 18 percent.

And who does the high-school dating system disadvantage most, statistically? Senior girls, at least according to the skew between stated sexual preferences and actual sexual activity. Though that will undoubtedly come as cold comfort to those legions of lonely 14-year-old boys.

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