The Measurement of Race/Ethnicity in Social Determinants of Health Literature: A Scoping Review

Background: The U.S. Multiracial population more than doubled from 2010 to 2020, partly due to improvements in how the U.S. Census measures racialized group/ethnicity. This growth highlights the impact of measurement on accurately classifying individuals' racialized/ethnic groups. Understanding which subpopulations face the greatest barriers to healthcare requires accurate classification of racialized and ethnic groups, making accurate measurement of racialized/ethnic group fundamental to health research, especially in studies focused on Social Determinants of Health (SDOH). When racialized or ethnic groups are misclassified in SDOH research, it can lead to inaccurate understandings of which populations are most affected by adverse conditions, misguiding both interventions and policy decisions. Purpose: This scoping review summarizes and synthesizes how racial/ethnic identity is measured among Multiracial individuals in United States-based health or SDOH studies.

Methods: Studies met the following inclusion criteria: 1) sample of 95%+ Multiracial individuals of any age, 2) conducted in the United States with a US sample (three studies had samples from the US and other countries), 3) focused on measurement practices classifying Multiracial identity, 4) examined SDOH outcomes, 5) written in English, and 6) published between 2014 and 2024. We used search terms related to Multiracial identity (e.g., Biracial, mixed race), racial classification; measurement; and health or SDOH. Following PRISMA-ScR guidelines, we collaborated with a behavioral health science research librarian to refine our search strategy across seven databases. The searches were conducted over two months, concluding in September 2024.

Results: From the initial 877 studies imported into Covidence for screening, after removing 652 duplicates and screening 191 full-text studies, the final results yielded 37 studies. These 37 studies employed various measures across 48 Multiracial subgroups while examining diverse health outcomes. Half (51%, n=19) used self-identified measures (e.g., “What is your race?”), reflecting a shift toward capturing more nuanced racialized identities. However, 43% (n=16) of the studies explicitly stated that a self-identification measure was utilized but 11% (n=4) of these studies employed a socially assigned measurement method (e.g., limited racial categorization based on societal standards). Socially assigned measures (e.g., check all that apply only; 30%, n=11) were prevalent. Quite a few studies (49%, n=18) used multidimensional approaches, integrating self-identification, social assignment, and/or ancestry, through comprehensive (i.e., two or more) measures. The response options for racial identity varied across studies, including write-in only (19%, n=7) and mixed methods (i.e., checkbox and write-in; 32%, n=12).

Implications: Expanding research on Multiracial populations is essential for advancing more robust methodologies, including the development of consistent, comprehensive and standardized comprehensive approaches to measuring racial identity. Comprehensive approaches that integrate self-identification with write-in options appear to offer the most accurate means of capturing racial identity. In contrast, socially assigned measures limit individuals’ ability to self-identify and may perpetuate inaccuracies. Adopting multidimensional frameworks will lead to more precise SDOH findings and help design interventions that promote racial health equity across increasingly diverse populations. Conclusion: As more individuals identify as Multiracial, more inclusive, consistent, and standardized measurement strategies are essential to improving the quality and equity of health research.