For decades, black parents have told their children that in order to succeed despite racial discrimination, they need to be “twice as good”: twice as smart, twice as dependable, twice as talented. This advice can be found in everything from literature to television shows, to day-to-day conversation. Now, a new paper from the National Bureau of Economic Research shows that when it comes to getting and keeping jobs, that notion might be more than just a platitude.

There’s data that demonstrates the unfortunate reality: Black workers receive extra scrutiny from bosses, which can lead to worse performance reviews, lower wages, and even job loss. The NBER paper, authored by Costas Cavounidis and Kevin Lang, of Boston University, attempts to demonstrate how discrimination factors into company decisions, and creates a feedback loop, resulting in racial gaps in the labor force.

The researchers constructed an economic model based on labor market outcomes for unemployed workers. They build on existing data about job duration, unemployment duration, and lifetime earnings, and then simulate how companies determine whether or not new hires are a good fit.

They observe that the pool of unemployed black workers is likely to be seen as less skilled because of more consistent or prolonged unemployment. That can make companies less likely to hire them, and more skeptical once they do. This leads employers to invest more heavily in monitoring black employees. That could be everything from instructing supervisors to closely watch a new hire, or more directly monitoring job performance—for instance how many boxes a worker correctly packs at a shipping center. Because black workers are more closely scrutinized, it increases the chances that errors—large or small—will be caught. According to the researchers it’s more likely that a black employee would be let go for these errors than a white one. Thus another way of looking at the findings, Lang says, is that blacks simply don’t get a second chance.