“Economists take a pretty unemotional approach to thinking about relationships,” says Leora Friedberg, sitting in the lounge of Monroe Hall, which houses UVA’s Department of Economics. “We focus on what we can quantify.”

Strange then, that Friedberg, an associate professor of economics, and her colleague, economics professor Steven Stern, have become experts on quantifying that most nebulous of feelings: love. And, like something out of a romantic comedy, love came into the equation (literally) when no one was looking for it. “The love discovery was a happy accident,” Stern says.


In 2003, Friedberg and Stern began examining a survey of more than 4,000 married couples, data collected at the University of Wisconsin from 1989 to 1994. Stern and Friedberg were researching bargaining theory in marriage—how spouses “bargain” to divide up all of the gains from marriage, such as raising children, getting to divide chores, or enjoying a larger income. The economists looked closely at replies to two particular questions the couples had been asked:

  • How happy are you in your marriage relative to how happy you would be if you weren’t in the marriage?
  • How do you think your spouse answered that question?

“These are very unique questions,” Friedberg says. As they describe in their paper, “Marriage, Divorce, and Asymmetrical Information,” published in the International Economic Review last fall, the economists took the information about how happy or unhappy spouses were, and how happy or unhappy they thought their partners were, and used it to predict how hard spouses were bargaining with one another.

“When it comes to bargaining, there’s a tradeoff,” Stern says. “On the one hand, each member of the couple wants to get as much as they can, and on the other hand, they both recognize that there are benefits to being together, and so they don’t want to get the other person to just walk away.”

“There’s a limit on how much you can bargain,” Friedberg says. “We initially just thought about using this information about happiness to put bounds on how tough each partner could be in marriage. That is to say if I see my spouse being really happy, then I can be a little tougher, and not drive them away. It’s a little cynical.”

“It’s a lot cynical,” Stern says, laughing.

Stern’s and Friedberg’s model predicted divorce rates based on whether they thought spouses were bargaining too hard. “We were predicting a lot of divorces, and also, we were predicting that even relatively happy couples could end up divorcing because they drove too hard a bargain,” Friedberg says.

When they examined the actual divorce rates of the surveyed couples (taken six years after the initial survey), the economists saw their numbers didn’t match up. They had predicted too many divorces.

“We found that that our model did not fit the data well in that it predicted that happy couples [those who both said they would worse off if they separated] would get divorced at approximately the same rate as unhappy couples,” Stern says. “In the data, 7 percent is the average divorce rate, but for happy couples, the rate was just around 3 percent, and for unhappy couples, it was 12 to 14 percent.”

“That was our eureka moment,” Friedberg says.

The economists realized they hadn’t taken caring, or love, into account when it came to their bargaining theory model. “Happy couples gain extra happiness from their spouse being happy, and so they don’t want to bargain that hard,” Friedberg says. “If they have some caring, and if they get some value from their spouse not being miserable, then that goes a long way to explaining the variations in divorce rates that we see.”

Friedberg and Stern realized they could actually model love in a quantitative way to understand the discrepancies in their predictions and the actual data. “We estimate what are called indifference curves, which is basically, ’how much of my own happiness am I willing to give up to make my spouse happier?’” Stern says. “The average is about .1, which means I’m willing to give up one unit of happiness if it makes her 10 units happier.”

And so there it is among equations and graphs: quantifiable evidence of love.

The economists emphasize that love can’t necessarily save an unhappy marriage. “Everyone loves,” Stern says. “It’s just that the unhappy couples don’t have a lot to bargain over. If Leora and I are married, and we’re really not that happy, she can’t give me that much to make me happier, because she’s not that happy.”

Friedberg agrees. “Love doesn’t really do much there to solve the problem … Some couples should get divorced. They’re just not generating enough happiness in the marriage.” She shakes her head and laughs. “Like I said before, economists take a hard-headed approach to thinking about relationships.”