In our complex religious landscape, quantifying solid research on evangelicals is essential. Yet this need has provoked a question which has frustrated researchers for half a century: Who is an evangelical?

Few identifiers are as ubiquitous but so poorly defined. The result has been that even premier polling groups are divided on who counts. To understand how we got here, I will give some background on research into evangelicalism and then offer a path forward.

In the wake of Jimmy Carter, existing and new polling agencies began to ask America’s first “born again” president and the evangelicals he claimed to represent what it was that made someone evangelical. Unfamiliar with evangelical language and belief, research institutions struggled to craft the right means of measuring the movement. This is reflected in the four initial Gallup polls listed below.

Notice that the meaning of the definition changes between each poll. Initially defining evangelicalism by behavior, Gallup switches to participation in a movement, returns to the original definition, and settles upon self-identification as an evangelical.

In the past 30 years, other research organizations have taken the lead in generating evangelical statistics. The Pew Forum on Religion and Life regularly publishes on the intersection of religion and politics, relying upon self-identification as means of defining evangelicalism. The Barna Group often publishes studies on evangelical social life and morality, depicting evangelicalism as the correlation of nine shared beliefs — ranging from the deity of Christ to certain specifics of the creation story of Genesis.

Yet these definitional variances predictably created a disparity in percentage of evangelicals studied, ranging from 7 percent (Barna, 1998) to 47 percent (Gallup, 1999). This variance across differing polls is largely the product of researchers categorizing evangelicals by one of three identifiers: behavior, belonging or belief.

The behavior approach to research examines church attendance, focusing on trends in religious participation and migration. However, limiting research to preset denominations leaves out evangelically-minded individuals who attend churches traditionally not associated with evangelicalism. This produces sensationalist headlines, yet presents data flawed by the exclusion of communities who consider themselves evangelical.

The belonging approach emphasizes self-identification over church attendance, asking the respondent if he or she is an evangelical. This tactic addresses the problem of the behavior approach in accounting for evangelicals across the denominational spectrum. However, emphasizing belonging is too simplistic. As seen in the Gallup polls above, through asking broad questions such as “Are you born again?” the poll is loaded with unintended baggage.

Turning to the belief approach, Baylor University launched a 2005 study to gather data on religion in America. Baylor went beyond simple questions to more in-depth inquires. Rather than asking, “Do you believe in God?” the respondent could define God (judgmental? forgiving? faithful?). This shift was a crucial step towards a workable definition, but it still raised questions about which beliefs are determinative of evangelicalism.

Enter National Association of Evangelicals President Leith Anderson. Responding to a LifeWay Research/NAE research initiative I oversaw in 2015, Anderson concluded that evangelicals must be defined primarily by their beliefs rather than politics or race. In the hopes of crafting a consensus definition of core evangelical beliefs, we evaluated the statements of a diverse group of sociologists, theologians and evangelical leaders. In weighing the insights of these leaders, LifeWay Research developed a definition of evangelical belief around strong agreement with these four statements:

  • The Bible is the highest authority for what I believe.
  • It is very important for me personally to encourage non-Christians to trust Jesus Christ as their Savior.
  • Jesus Christ’s death on the cross is the only sacrifice that could remove the penalty of my sin.
  • Only those who trust in Jesus Christ alone as their Savior receive God’s free gift of eternal salvation.

Mirroring historian David Bebbington’s classic four-point definition (conversionism, activism, biblicism and crucicentrism), research suggests that these beliefs form the interconnected statistical construct that points towards evangelicalism.

Under this rubric, about three in 10 Americans count as evangelical. Of all respondents, more than half strongly agreed that the Bible is their highest authority (52 percent) and that Jesus’ death is the only sacrifice that could remove the penalty of sin (58 percent). Almost as many strongly agreed that it is important for them to personally encourage non-Christians to trust Christ (49 percent) and that only those who trust solely in Jesus will receive eternal life (48 percent).

This belief-centered approach to research also aligns with the behavior and belonging approach. Those who strongly agree with all four are more likely to attend church frequently and identify themselves as evangelical. In effective research, behavior and belonging provide important information on trends in broader culture, but measuring the constitutive beliefs of evangelicalism is vital in defining the movement.

Perhaps most important, this belief-centered approach includes evangelicals who are commonly missed by other studies. Although African American Christians have historically aligned with evangelical beliefs, they use the identifier language less frequently. Only 25 percent of African Americans who hold evangelical beliefs used the term, compared to 62 percent of whites and 79 percent of Hispanics. As for church affiliation, 23 percent of Catholics and 47 percent of Protestants hold evangelical beliefs.

As such, I believe a belief-centered approach offers a helpful pathway for researchers to more clearly identify the evangelicals and avoid the pitfalls of behavior and self-identification.

Most importantly, in a moment when “evangelical” is too often seen as “white evangelical” without connecting evangelicals with a movement that is theological misunderstands the nature of the movement. This, in turn, perpetuates an approach to identification that creates a picture of evangelicals that is white even as evangelicalism is now (and increasingly) diverse.

This article originally appeared in Evangelicals magazine.