Part of the reason implicit bias has such a strong impact across every aspect of life is because it happens subconsciously—even among the well-intentioned. Unlike overtly held beliefs, implicit biases are formed based on "implicit attitudes" (the tendency to like/dislike members of a racial group) and "implicit stereotypes" (association of a race with a particular trait). These are cognitive functions that take place out of our conscious focus, so we can exhibit implicit bias even when we don't endorse the underlying attitude or stereotype. However unconscious, these biases can result in racist behavior, and the effect is no less severe.

While a growing body of research examines the value of teachers of color for students of color, there is relatively little research in the U.S. on implicit bias and its effect on student achievement. Mark Chin (Harvard University) and a team of researchers aimed to tackle this in a recent study that focused on (1) identifying teachers' White/Black implicit biases and with what characteristics they are correlated—be it individual (e.g. teacher's gender or race); contextual (e.g. racial composition of the student body or average SES); or instructional (e.g. average per pupil instructional expenditure or student-teacher ratios); and (2) whether White/Black implicit or explicit bias is correlated with disparities in test scores and/or suspensions.

Using nationwide and county-level data, Chin et al. found that teachers of color have significantly lower average bias than White teachers, with Black teachers showing the lowest levels of bias. Additionally, female teachers, in general, are slightly less likely to be biased.

The researchers also found variations among counties, with teachers' adjusted bias levels being lower in counties with larger shares of Black students, though the researchers could not speak to why this is the case. (Do teachers with lower bias choose to work in more racially diverse districts? Are teachers with lower bias more likely to be hired and/or persist in these districts?)

Importantly, Chin et al. found larger Black/White disparities in both test scores and suspensions in counties with higher aggregate levels of pro-White/anti-Black bias among teachers, providing suggestive evidence of the negative impact of implicit bias on students.

While the findings are not all that surprising (negative racial biases hurt students of color), what is perhaps most important about the study is that the researchers controlled for a variety of factors that many would proffer as solutions—like increasing spending per student or lowering the student teacher ratio (which would presumably support better relationships between teachers and students)—and found no relationship with levels of bias.

The lack of a relationship highlights the very real need for intentional action aimed specifically at mitigating the effects of implicit racial biases on students of color. As a number of other studies have shown, this is easier said than done, as many of the solutions just aren't that effective. In fact, new research suggests that given how long it takes to change individuals' biases, education leaders might be better off focusing on explicit protocols (like clearly defined grading rubrics) instead of expensive, ineffective "anti-bias" training that rarely produces intended results.