Replication Data for: What Happens When You Can’t Check the Box? Categorization Threat and Public Opinion among Middle Eastern and North African Americans

The following describes the data files, code and programs used to produce the figures and tables displayed in the manuscript, “What Happens When You Can’t Check the Box? Categorization Threat and Public Opinion among Middle Eastern and North African Americans,” as well as in the supplemental materials. All required packages are included at the start of each script file. Abstract: Middle Eastern and North African (MENA) Americans occupy a paradoxical position: a highly politicized, highly visible group rendered institutionally invisible by the absence of an official ethnoracial category. From 1977 to 2024, the federal government categorized MENA Americans as “White.” Despite this categorization, research shows that they are neither perceived as White nor identify as such, often preferring to self-categorize as “MENA.” Yet many forms—whether issued by governments, universities, or private organizations—rarely include “MENA” as an option. What are the consequences of having one’s identity omitted on political attitudes related to that identity? I argue that denying MENA Americans the ability to self-categorize induces categorization threat, a response well-documented in social psychology but less often connected to politics. Drawing on two survey experiments and in-depth interviews, I show that MENA individuals who cannot self-categorize as “MENA” engage in identity assertion by expressing stronger opinions on MENA-related political issues. This assertion may also generalize to issues tied to broader “People of Color” (POC) identity. Identity categories are not merely bureaucratic formalities; they structure how individuals see themselves and how they respond to politics. By showing that categorization threat shapes political expression among MENA Americans, this article underscores how institutional categories can marginalize groups and affect the validity of the data used to govern them. As identities become increasingly complex and salient, understanding the consequences of category exclusion becomes vital for both empirical research and democratic inclusion.