Why America’s Multiracial Population Boom Exposes Flaws in Race Data Systems

America is becoming more multiracial, but its data systems remain stuck in a binary view of race. Outdated measurement systems shape how elections are analyzed, health risks are tracked, and civil rights laws are enforced.

The multiracial population—defined by the U.S. Census as people who identify with "Two or More Races"—grew from 9 million in 2010 to 33.8 million in 2020. This group is projected to expand faster than most racial demographics, but the pace depends as much on how America measures race as on how people live and understand their identities.

How Race Measurement Has Evolved

Before the 1960s, race was often assigned by census takers. Today, it is largely self-identified. The U.S. Census now allows respondents to "mark one or more" racial categories. However, people frequently change how they identify across surveys and contexts. A multiracial individual may report two races in one questionnaire but a single race in another.

The Challenge of Classifying a Diverse Group

Even basic analysis is difficult because the "multiracial population" is not a monolithic group. Census data includes 57 distinct racial combinations, according to a study by UCLA’s The Civil Rights Project. The report questions whether a person who identifies as mixed-race white and Black shares the same racialized experiences as someone who identifies as mixed-race Japanese and Mexican.

Consequences of Miscounting Multiracial Americans

When multiracial Americans are miscounted or inconsistently classified, the ripple effects are felt across critical systems:

• Healthcare: Studies show multiracial patients face misidentification and racial microaggressions in clinical settings, which can erode trust and reduce engagement with medical care.
• Legal System: Courts often treat multiracial plaintiffs as belonging to a single minority group, obscuring the nuances of mixed-race discrimination, legal scholars argue.
• Redistricting: Census classification rules can reassign multiracial people into single racial categories, impacting political representation and enforcement of civil rights laws.

Why Experts Say the Data System is Broken

"The boundaries of race have become more fluid, and we've not fully reconciled what that means."

— Gregory Leslie, political psychologist at The Ohio State University and co-author of the UCLA report

Leslie notes that multiracial Americans defy traditional assumptions, with identities and affiliations shifting based on environment and experience. "There are so many different ways to measure. The data is hard to get because we're measuring something dynamic with static categories," he tells Axios.

Real-World Example of Data Inconsistencies

A multiracial respondent with one white parent and one Asian parent may identify as both races in one survey but as only Asian in another. People who strongly align with a political party or community are more likely to choose a single racial identity that reflects that affiliation—meaning identity choices can systematically skew data. Two datasets measuring the same population can yield conflicting conclusions about political behavior, inequality, or even population size.

The Stakes Go Beyond Demographics

Mixed-race individuals often experience discrimination similar to single-race minorities, the UCLA report found. However, outcomes vary sharply: multiracial Americans with Black ancestry report higher rates of discrimination than other groups. Algorithms that rely on flawed racial data can perpetuate bias in hiring, lending, and policing.