Giving People Information Changes Behavior


Last week I wrote that if kids in school had a better idea of the extent to which dropping out of high school correlates with being unemployed, that they might work harder and stay in school and that this, in turn, would improve their lives. The most popular source of pushback I got on this basically followed the Jon Chait school of thought:

Without seeing the data, I strongly suspect otherwise. I’m guessing the things that make people unable or unwilling to finish high school also make them bad at acquiring and holding jobs. Which is to say, even if you took the high school dropouts and managed to get all of them through school, giving them the benefit of additional school knowledge but not changing anything about their work habits, health, intelligence, environmental pressures, and so on, they’d have much higher levels of unemployment anyway.

I don’t think you learn a lot of job-relevant skills in 12th grade, and I suspect even the signalling value to employers of a high school degree is not all that valuable, either.

This seems to me like a great case study in how strong the signaling value of a high school diploma is. Failure to receive one is such an overwhelmingly negative signal that smart policy writers dismiss out of hand the possibility that poor outcomes for the diplomaless might reflect a signaling problem. It just seems obviously that lack of diploma correlates so strongly with disfavored personality characteristics such that the rational employer will use possession (or lack thereof) of a high school diploma as a criteria for employment. That, in turn, bolsters the case that a teenager who understands the situation ought to suck it up and finish high school. It’ll help him signal good qualities. But guess work? Doing the stuff it takes to finish school, even with bad grades, necessarily involves a change in work habits and environment! So if more people understood the (large) signaling value of a high school diploma the actual level of human capital would improve.

Is that really true? Well, it’ll be hard to know without an experiment. But several things I’ve read recently have convinced me that “give people some information” is an underrated social policy intervention. Poor Economics (which is about third world poverty, not rich country poverty) from Esther Duflo and Abhijit Banerjee contains a number of examples, of which this is one:

The second strategy just involved telling the girls something they did not know: the fact that older men are more likely to be infected with HIV than younger ones. A striking feature of HIV is that women from the ages of fifteen to nineteen are five times more likely to be infected than young men in the same cohort. This seems to be because young women have sex with older men, who have comparably high infection rates. The “sugar daddies” program simply informed students about what kind of people are more likely to be infected. Its effect was to sharply cut down sex with older men (the “sugar daddies”) but, also interestingly, to promote protected sex with boys their own age. After a year, the pregnancy rates were 5.5 percent in schools that had not received the program and 3.7 percent in schools that had received it. This reduction was mainly attributable to a reduction by two-thirds in pregnancies where an older male partner was involved.

The fact that ceteris paribus an older man is more likely to be infected than a younger one seems obvious once you think about it. But evidently many of the young women in the country where this experiment was performed haven’t thought about it. Telling them changed behavior.

Across a whole range of domains, teenagers make choices that have pretty drastic consequences for their lives. And teenagers are often quite ignorant. Many don’t know who Osama bin Laden is. So how many of them are aware of the statistical correlations between educational attainment and employment or age and STD infection?