A college degree is generally a good bet, but it’s not enough to protect you from poverty.

The Census Bureau’s annual report on income and poverty released Wednesday highlights this depressing fact. Among bachelor’s degree recipients, roughly 3.6 million or 4.8% were living in poverty in 2017, according to the Census Bureau. That’s up from 3.3 million and 4.5% in 2016. Bachelor’s degree recipients were the only educational cohort to see the number or the share of people in poverty rise among their ranks.

It’s still too early to tell whether the uptick in bachelor’s degree recipients living in poverty is a true trend or a statistical blip. The 0.3 percentage point increase in the share of college-educated Americans in poverty is about the same as the report’s margin of error for that finding. Still, “this is something we want to watch,” said Doug Webber, an economics professor at Temple University.

What’s more, the mere fact that millions of college-educated Americans are living in poverty adds another data point to the increasingly complicated picture of a college degree’s value in the labor market. On the one hand, a degree is more necessary than ever to succeed in today’s economy — those with a bachelor’s degree or above are the least likely to be in poverty, according to the Census Bureau; on the other hand, getting a degree still involves some risk.

“While workers with a college degree in general have lower unemployment rates, higher earnings, lower poverty rates and, on average, they have much better outcomes, those are averages,” said Heidi Shierholz, senior economist at the Economic Policy Institute, a left-leaning think tank. “It’s a worthwhile reminder that there are people with college degrees that are living in poverty — they can’t find a job with good wages, they can’t find a job at all.”

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Though we don’t have enough information to say definitively that the number of college graduates living in poverty is rising, there are some reasons why more college graduates than in the past may be struggling.

For one, the supply of college graduates is now larger. In general, a college degree is still a good bet, but it doesn’t send the same signal to employers that it did 10, 20 or 30 years ago, Webber said. “You’re not setting yourself apart from all of the rest of the population now, to the same degree that a bachelor’s degree signaled several decades ago,” he said.

The variation in type and quality of bachelor’s degrees has also increased over the past several years, which may explain why some college graduates still struggle to get by. The explosion in for-profit college enrollment, particularly during the recession, means there are likely more graduates out there with bachelor’s degrees that aren’t necessarily helping them in the labor market.

There’s evidence to indicate that many for-profit college chains did worse on average when it comes to graduates landing a decent job or repaying student loans than other types of colleges. “We have this mechanism out there that is more likely to provide people with college degrees that aren’t high quality,” Shierholz said.

There’s also a much larger variation in the types of people attending college these days, which may explain in part why more students struggle after graduating. In the past, students attending college were generally 18 to 22 year-olds from middle-class or even wealthier backgrounds. Today’s college student is more likely to be a working parent returning to school or someone from a low-income background; these factors can make economic mobility difficult, even with a college degree.

“Let’s say you’re an older person contemplating whether to go back to school or not, who’s going to be the type of person who does go back to school?” Webber said. People who were already struggling in the labor force and were, perhaps, near the margin of poverty already, he said. “If that’s the reason that you chose to go back to school and you got that bachelor’s degree, you’re also more likely to be on that margin after school.”

Finally, general labor market trends may also be contributing to the plight of college graduates. For the past several decades, the gap between the earnings of those at the top and those at the bottom of the wage scale has been growing, Shierholz said, but that trend really started to hit college graduates around 2000. “Those same trends of stagnant wages now also apply to workers with a college degree,” she said.

It’s still too early to say how best to address the problem of rising levels of struggling college graduates, Webber said, mostly because it’s still too early to tell whether it’s even a problem at all. And the fixes may be different depending on the cause.

If, for example, the rise in for-profit colleges is largely to blame then a targeted solution like regulations that specifically address issues in that sector could offer a fix. If, on the other hand, it’s a broader labor market problem, it’s more difficult to come up with a clear policy response, he said.

“It’s very premature to talk about that now,” Webber said of possible policy remedies. But as is often the case with economic policy-making “by the time we have enough data to actually say there definitely is a problem then there are already a number of people who have been hurt by it.”