Few issues in the U.S. today are as controversial as diversity, equity, and inclusion—commonly referred to as DEI. Although the term didn’t come into common usage until the 21st century, DEI is best understood as the latest stage in a long American project. Its egalitarian principles are seen in America’s founding documents, and its roots lie in landmark 20th-century efforts such as the 1964 Civil Rights Act and affirmative action policies, as well as movements for racial justice, gender equity, disability rights, veterans, and immigrants. These movements sought to expand who gets to participate in economic, educational, and civic life. DEI programs, in many ways, are their legacy. Critics argue that DEI is antidemocratic, that it fosters ideological conformity, and that it leads to discriminatory initiatives, which they say disadvantage white people and undermine meritocracy. Those defending DEI argue just the opposite: that it encourages critical thinking and promotes democracy—and that attacks on DEI amount to a retreat from long-standing civil rights law. Yet missing from much of the debate is a crucial question: What are the tangible costs and benefits of DEI? Who benefits, who doesn’t, and what are the broader effects on society and the economy? As a sociologist, I believe any productive conversation about DEI should be rooted in evidence, not ideology. So let’s look at the research. Who gains from DEI? In the corporate world, DEI initiatives are intended to promote diversity, and research consistently shows that diversity is good for business. Companies with more diverse teams tend to perform better across several key metrics, including revenue, profitability, and worker satisfaction. Businesses with diverse workforces also have an edge in innovation, recruitment, and competitiveness, research shows. The general trend holds for many types of diversity, including age, race, and ethnicity, and gender. A focus on diversity can also offer profit opportunities for businesses seeking new markets. Two-thirds of American consumers consider diversity when making their shopping choices, a 2021 survey found. So-called “inclusive consumers” tend to be female, younger, and more ethnically and racially diverse. Ignoring their values can be costly: When Target backed away from its DEI efforts, the resulting backlash contributed to a sales decline. But DEI goes beyond corporate policy. At its core, it’s about expanding access to opportunities for groups historically excluded from full participation in American life. From this broader perspective, many 20th-century reforms can be seen as part of the DEI arc. Consider higher education. Many elite U.S. universities refused to admit women until well into the 1960s and 1970s. Columbia, the last Ivy League university to go co-ed, started admitting women in 1982. Since the advent of affirmative action, women haven’t just closed the gender gap in higher education—they outpace men in college completion across all racial groups. DEI policies have particularly benefited women, especially white women, by expanding workforce access. Similarly, the push to desegregate American universities was followed by an explosion in the number of Black college students—a number that has increased by 125% since the 1970s, twice the national rate. With college gates open to more people than ever, overall enrollment at U.S. colleges has quadrupled since 1965. While there are many reasons for this, expanding opportunity no doubt plays a role. And a better-educated population has had significant implications for productivity and economic growth. The 1965 Immigration Act also exemplifies DEI’s impact. It abolished racial and national quotas, enabling the immigration of more diverse populations, including from Asia, Africa, southern and eastern Europe, and Latin America. Many of these immigrants were highly educated, and their presence has boosted U.S. productivity and innovation. Ultimately, the U.S. economy is more profitable and productive as a result of immigrants. What does DEI cost? While DEI generates returns for many businesses and institutions, it does come with costs. In 2020, corporate America spent an estimated $7.5 billion on DEI programs. And in 2023, the federal government spent more than $100 million on DEI, including $38.7 million by the Department of Health and Human Services and another $86.5 million by the Department of Defense. The government will no doubt be spending less on DEI in 2025. One of President Donald Trump’s first acts in his second term was to sign an executive order banning DEI practices in federal agencies—one of several anti-DEI executive orders currently facing legal challenges. More than 30 states have also introduced or enacted bills to limit or entirely restrict DEI in recent years. Central to many of these policies is the belief that diversity lowers standards, replacing meritocracy with mediocrity. But