There is a growing body of research showing that minorities face bias in the job application process. When identical resumes — one with the name Emily and one with the name Lakisha, for example — are sent to job openings, Emily’s resume gets substantially more callbacks. And even with the same credentials as other candidates, minorities are less likely to be hired.
But we know considerably less about how bias plays out when minorities are hired, especially when it comes to on-the-job performance and productivity. Recent research I conducted along with Dylan Glover and William Pariente, forthcoming in the Quarterly Journal of Economics, attempts to address this gap. We find that when managers hold negative beliefs, even unconscious ones, about minority workers, minority employees perform much worse than they do with unbiased bosses. In other words, managers’ biases can become self-fulfilling prophecies.
Our study involved newly hired cashiers in 34 outlets of a French grocery store chain. These cashiers were ideal to study because they worked with different managers on different days, so we could compare the same worker’s performance under different managers. They had no control over their schedules or which managers they worked with, so they couldn’t avoid supervisors they disliked. Moreover, workers’ schedules were determined quasi-randomly by a computer program, which ensured that all employees worked with the same managers under similar conditions.
We classified workers of North or Sub-Saharan African origin as minorities, identifying these workers based on the origin of their names because it’s illegal in France to ask a worker about their ethnicity. We measured managers’ bias toward minorities with an Implicit Association Test (IAT), which is widely used in psychology to measure unconscious bias. This test has been found to predict many real-world decisions, and it is hard for subjects to manipulate their answers to appear unbiased.
The test involves categorizing two sets of words to the left- and right-hand sides of a computer screen. In our case, managers were presented with (1) names typically indicating a French origin or names traditionally indicating a North African origin and (2) adjectives that describe good employees or adjectives that describe bad employees. One word at a time came onto the screen, and subjects were told the categorization rules (for example, adjectives describing good employees were on the left, adjectives describing bad employees were on the right). Names and adjectives were interspersed and managers were instructed to categorize the words as quickly as possible. In one round, managers were told to categorize French-sounding names and negative adjectives to the same side of the screen, while in the other they were tasked with categorizing North African–sounding names and negative adjectives to the same side. Managers’ bias was measured by how much more quickly they categorized words when North African–sounding names and negative adjectives were categorized on the same side of the screen.
Once we had this information, we were able to analyze this data along with a variety of worker performance measures. We found that minorities performed much worse when they work with biased managers. For one thing, they knew ahead of time which manager they would be working with, and they were much more likely to be absent when paired with a biased one. When they did go to work, they were much less likely to stay late. Because they were paid based on time worked, we estimated they earned 2.5% less as a result of manager bias. They also scanned items more slowly and took more time between customers.
Overall, minorities in these stores performed on par with other workers. However, when minority employees worked with unbiased managers, they served 9% more customers than other workers and ranked in the 79th percentile of worker performance.
It’s important to note that biased managers are not simply bad managers who lead all their workers to perform poorly. Workers not classified as minorities in our study performed equally well under both biased and unbiased managers. In fact, none of the negative effects from working with biased managers can be explained by other manager characteristics, including the managers’ own ethnicity.
Why does manager bias impact worker performance? Surprisingly, it’s not that biased managers explicitly treat minorities poorly. On a survey conducted after workers’ contracts at the grocery store ended, minorities did not report that biased managers disliked them or that they disliked biased managers. Nor did they report that biased managers would be less likely to recommend them for promotion. In fact, they said that biased managers treated them better in that they were less likely to assign them to cleaning, the least pleasant of their tasks, and were no more likely to assign them unpleasant registers or breaks.
Minorities simply had less interaction with biased managers during their shifts. It seems that managers didn’t pay as much attention to them. This is consistent with research that finds that individuals with implicit biases toward a group are less likely to speak to, more hesitant in speaking to, and less friendly toward group members. In our study, managers may have been uncomfortable interacting with minority workers, so they simply spent less time managing them. The result was a drop in employee productivity.
While there’s still a lot to learn about how manager bias impacts the relationships between managers and employees, our research shows that it has important consequences for worker performance. In grocery stores, for example, managers have comparatively little control over workers because cashiers largely complete the same task, scanning groceries, on their own no matter which manager they work with (albeit more slowly or more quickly). In other settings, where managers work directly with employees and have more say over their assignments, manager bias may generate even larger losses in performance if it leads them to train, mentor, advise, or challenge minorities less.