RELTRAD Affiliation Classification
Also known as: Religious Tradition Coding, RELTRAD Scheme, Denominational Classification Scheme, Religious Affiliation Coding
Religious affiliation classification is the task of turning hundreds of detailed denominational responses on a survey into a small, analytically useful set of religious traditions. The dominant scheme, RELTRAD, was proposed by Brian Steensland and colleagues in their 2000 Social Forces article 'The Measure of American Religion,' which criticized earlier classifications as historically and theologically incoherent and offered seven categories grounded in the development of American religious traditions: evangelical Protestant, mainline Protestant, Black Protestant, Roman Catholic, Jewish, other faiths, and no religion. By sorting respondents into traditions that share a meaningful religious heritage rather than into ad hoc groupings, RELTRAD became the standard variable through which sociologists relate religion to politics, family, and social attitudes.
Key highlights
- Groups denominations by genuine historical tradition rather than an arbitrary liberal-conservative axis.
- Provides explicit, published coding rules that make classification reproducible across datasets.
- Distinguishes the historically Black Protestant tradition, which prior schemes often submerged.
- Yields categories that behave coherently on attitudes and behavior, improving downstream analysis.
Intuition
This section is available to Pro members. Upgrade to Pro
How it works
This section is available to Pro members. Upgrade to Pro
When to use it
Use RELTRAD affiliation classification whenever you need to convert detailed denominational survey responses into a manageable, meaningful set of religious traditions for analysis of American religion. It is appropriate when the survey collected sufficiently detailed affiliation (and, for the Black Protestant category, respondent race), and when you want categories that group denominations by shared heritage rather than by an ideological axis. It is the standard choice for studying how religion relates to politics, family, and social attitudes in the United States. It is less suitable for non-U.S. contexts whose religious landscapes RELTRAD was not built for, for surveys lacking detailed denomination, or for questions where within-tradition heterogeneity is the focus and the seven broad categories would obscure it.
Strengths & limitations
- Groups denominations by genuine historical tradition rather than an arbitrary liberal-conservative axis.
- Provides explicit, published coding rules that make classification reproducible across datasets.
- Distinguishes the historically Black Protestant tradition, which prior schemes often submerged.
- Yields categories that behave coherently on attitudes and behavior, improving downstream analysis.
- Requires detailed denominational data and respondent race, which not all surveys collect.
- Tailored to the U.S. religious landscape and does not transfer cleanly to other countries.
- The seven broad categories can mask substantial heterogeneity within traditions, especially evangelicalism.
- Coding decisions for ambiguous or nondenominational responses remain judgment calls that affect results.
Common pitfalls
This section is available to Pro members. Upgrade to Pro
Applications
This section is available to Pro members. Upgrade to Pro
Frequently asked
What are the categories in the RELTRAD scheme?
RELTRAD sorts respondents into seven mutually exclusive religious traditions: evangelical Protestant, mainline Protestant, Black Protestant, Roman Catholic, Jewish, other religions, and no religious affiliation. These categories are defined by shared historical and theological heritage rather than by a single liberal-conservative axis, which is what distinguishes RELTRAD from the earlier schemes Steensland and colleagues criticized. The three-way split among Protestants is the scheme's most consequential feature.
Why does RELTRAD use respondent race in coding?
Because the historically Black Protestant churches form a distinct religious tradition with their own denominations, theology, and social role, but many Black Protestants belong to denominations - or report affiliations - that overlap with predominantly white evangelical or mainline bodies. Using respondent race to assign members of historically Black denominations, and Black members of other Protestant bodies, to the Black Protestant category keeps this tradition analytically visible. Omitting race would scatter the Black church across other categories and erase a meaningful distinction.
Why not just classify denominations as liberal or conservative?
Steensland and colleagues argue that a single ideological axis misrepresents American religion. Denominations differ along many historical and theological lines, and ranking them as more or less liberal lumps together bodies with very different heritages while splitting apart bodies that belong together. RELTRAD instead groups by tradition, which yields categories that are internally coherent and externally distinct on the outcomes researchers study, producing more interpretable and reproducible analyses than an ideology-based ranking.
Sources
- 1.Steensland, B., Park, J. Z., Regnerus, M. D., Robinson, L. D., Wilcox, W. B., & Woodberry, R. D. (2000). The Measure of American Religion: Toward Improving the State of the Art. Social Forces, 79(1), 291-318.
You have read it. What now?
Cite this page
ScholarGate. (2026, June 23). RELTRAD Affiliation Classification. ScholarGate. https://scholargate.app/sociology-of-religion/religious-affiliation-classification