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U.S. Religion Census - Religious Congregations and Membership Study, 2010 (State File)




Grammich, C., Hadaway, K., Houseal, R., Jones, D. E., Krindatch, A., Stanley, R., & Taylor, R. H. (2018, December 11). U.S. Religion Census Religious Congregations and Membership Study, 2010 (State File).


This study, designed and carried out by the Association of Statisticians of American Religious Bodies (ASARB), compiled data on the number of congregations and adherents for 236 religious groups in each county of the United States. Participants included 217 Christian denominations, associations, or communions (including Latter-day Saints, Messianic Jews, and Unitarian/Universalist groups); counts of Jain, Shinto, Sikh, Tao and National Spiritualist Association congregations, and counts of congregations and adherents from Bahá'ís, three Buddhist groupings, four Hindu groupings, four Jewish groupings, Muslims and Zoroastrians. The 236 groups reported a total of 344,894 congregations with 150,686,156 adherents, comprising 48.8 percent of the total U.S. population of 308,745,538 in 2010.

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Data File

Cases: 51
Variables: 565
Weight Variable: None

Data Collection


Original Survey (Instrument)

RCMS 2010 Website

Funded By

The Lilly Endowment, Inc.; The John Templeton Foundation; Evangelical Lutheran Church in America; North American Mission Board of the Southern Baptist Convention

Collection Procedures

The Church of the Nazarene Global Ministry Center in Lenexa, Kansas carried out the actual data collection. Richard Houseal, Research Services Manager, oversaw the data collection. Following the initial written invitation, two additional general mailings were sent. Those not responding to these received still additional special letters, personal contacts, emails, and phone calls. Altogether, 296 groups were invited to participate; of which 236 are included in the study. Seven groups intended to participate but did not, four declined to participate and 49 did not respond in any way.

Groups agreeing to participate were asked to appoint a contact person. Two forms were sent to the contact person: instructions for reporting data and a transmittal sheet to be signed and sent with the data collected. When requested, a state-county form for listing the statistics was provided. Contact persons could provide the data electronically, in printout, or using the state-county listing provided by the Church of the Nazarene Research Services staff.

The process put the major burden of work on the offices of the various religious groups, since they were asked to compile data by county for all their congregations. In some cases, however, groups were able to furnish information only in the form of yearbooks or other sources. Transferring yearbook information into county data then became the responsibility of the Church of the Nazarene Research Services staff. In a few cases, the groups instructed the staff to estimate congregational membership according to some formula, and approved the result. In all instances, the contact person was asked to review the statistics.

The Research Services staff employed standard procedures for checking the accuracy of data submitted. This included checking state and national totals against county data and adjusting discrepancies (reviewing adjustments with the contact person) and, when appropriate, applying the estimating procedure for adherents. Several items were prepared for review by the contact person. These included a spreadsheet of the data that compared 2000 figures to 2010 figures for each county and state, as well as a series of maps comparing 2000 and 2010 presence by county, and, for 2010, location of congregations, ratio of adherents to each county's population, and number of adherents by county. Only after all problems raised by both the staff and the contact person were resolved were the statistics considered ready for publication. The final step was to run a series of computer edit tests to check for errors. Finding incorrect county codes and locating records with no data were the most common corrections at that step.

Sampling Procedures

The sponsors invited all religious bodies that could be identified as having congregations in the United States to participate. In 2009, an invitation to participate in the study was sent to every U.S. religious body listed in the Yearbook of American and Canadian Churches. Invitations also were sent to contacts suggested by the Advisory Committee and by members of the ASARB. Several special efforts were made to identify and include data from several religious bodies that have not traditionally participated or been underrepresented in similar past studies. These included independent or non-denominational churches, Jewish synagogues, historically African American churches, Hindus, Buddhists, and Muslims. These efforts are described below.

Principal Investigators

Clifford Grammich, Kirk Hadaway, Richard Houseal, Dale E. Jones, Alexei Krindatch, Richie Stanley, Richard H. Taylor

Related Publications

Clifford Grammich, Kirk Hadaway, Richard Houseal, Dale E. Jones, Alexei Krindatch, Richie Stanley, and Richard H. Taylor. 2012. 2010 U.S. Religion Census: Religious Congregations & Membership Study. Association of Statisticians of American Religious Bodies.

Note on Membership Data

In an effort to achieve comparability of data, the ASARB staff established two major categories for individuals affiliated with a religious body: members and adherents. The ARDA data set contains only adherent totals. Below is a description of the two categories:

MEMBERS: all individuals with full membership status

TOTAL ADHERENTS: all members, including full members, their children and the estimated number of other participants who are not considered members; for example, the "baptized," "those not confirmed," "those not eligible for Communion," "those regularly attending services," and the like

Of the 236 reporting groups, 49 reported members and adherents; 37 reported adherents only; 63 reported members only; four suggested a method for estimating adherents without reporting members; and 83 reported only congregation locations. Of the 63 that reported members only, four suggested their own adherent estimating processes, which we used to calculate adherents for them. For those 59 groups that reported members but did not report adherents nor suggest a method for computing them, we estimated total adherents for each county by dividing membership by the population at least 14 years of age and then applied this percentage to the Census 2010 100-percent count for the county.

There are 31 counties or equivalents for which the number of reported adherents exceeds the total population in 2010. Reasons for the discrepancy will differ from county to county, but the most plausible would include U.S. Census undercount, church membership overcount, and county of residence differing from county of membership. This is especially likely in Virginia, where many cities have been separated from their adjoining counties.

African American Churches

For the 2010 U.S. Religion Census, researchers obtained mailing lists for the eight largest historically African-American denominations: the African Methodist Episcopal Church; the African Methodist Episcopal Zion Church; the Christian Methodist Episcopal Church; the Church of God in Christ; the National Baptist Convention of America, Inc.; the National Baptist Convention, USA, Inc.; the National Missionary Baptist Convention, Inc.; and the Progressive National Baptist Convention, Inc. The reported membership totals on the address lists represented less than 50 percent of any of these groups' churches or members as reported in the Yearbook of American and Canadian Churches, 2010. However, since the available locations did represent nearly four million people associated with specific religious congregations, the researchers decided to include these data in the 2010 Religion Census regardless of whether additional information could be obtained. Further efforts were made to gather denominational statistics. Preliminary results were shared with the groups, but none were able to supply further information. However, three groups did have online church locators, so additional congregation locations were identified for the African Methodist Episcopal Church, African Methodist Episcopal Zion Church and Christian Methodist Episcopal Church. For each congregation located in this way, a membership of 100 was assigned. This represented the modal size of Protestant churches that were reported to the data collection office.

These methods yielded figures that are significantly lower than those reported by the denominations in the Yearbook of American and Canadian Churches, 2010. For example, the U.S. Religion Census includes roughly the same number of congregations belonging to the African Methodist Episcopal Church, but only about one-third of the membership total reported in the Yearbook. For other groups, congregation counts range from 11 percent to 50 percent of reported numbers in the Yearbook, and membership figures are from 7 percent to 28 percent of reported amounts. An adherent formula was used to account for children likely to be associated with each church in addition to adult members. The result is 4,877,067 adherents identified as part of eight historically African American denominations in the United States in 2010. Additionally, three smaller church bodies that had online directories available are described as predominantly African American: Church of Our Lord Jesus Christ of the Apostolic Faith, Inc.; Cumberland Presbyterian Church in America; and United Holy Church of America, Inc. No adherent information was available, so only the locations are included in this study.

Jewish Estimates

The congregational arms of the Conservative (United Synagogue for Conservative Judaism), Reconstructionist (Jewish Reconstructionist Federation) and Reform (Union for Reform Judaism) movements provided the ASARB with lists of their synagogues and exact membership totals (or estimates) for each congregation. For Orthodox synagogues, the main national congregational body, the Union of Orthodox Jewish Congregations (Orthodox Union or OU), provided a list of its synagogues and membership totals. In addition, the website for the National Council of Young Israel lists the names and locations of all Young Israel congregations, an additional source of Orthodox congregations. In addition, researchers consulted the websites of every Jewish Federation in the United States to check for other Orthodox congregations not otherwise found and we consulted a variety of other local and national websites catering to the Orthodox community.

Jewish congregations record their size in terms of "member units" or entire households who pay membership dues. To estimate the number of adherents for each Jewish denomination the number of its households was multiplied by the mean number of its household members (Jewish or not) derived from the 2001 National Jewish Population Survey. The resulting estimate for the four groups combined is 2,256,584 adherents. This is significantly lower than the single estimate of 6,141,325 Jewish adherents in 2000. By comparison, 1.8 percent of General Social Survey respondents self-identified as Jewish in 2010, compared with 2.2 percent in 2000. Thus, the discrepancy likely reflects a change in methodology as well as real decline.

Muslim Estimates

An initial mosque estimate was compiled from the list in the 2000 Masjid Study and three online sources: 1) Muslim Guide, (2) Islamic Finder, and (3) Salatomatic. Local Muslims were contacted to verify information on existing mosques and identify mosques not on our list. Most local Muslims were representatives of local chapters of the Council on American-Islamic Relations (CAIR). The Islamic Shura Council of Southern California also assisted. In New York City, the Center for American Muslim Research and Information helped. Based on these efforts over 1,900 mosques were identified. Interviewers conducted a phone interview with mosque leaders and were asked to modify the existing list as they located mosque leaders. Through this process the original list was expanded to its final number of 2,106 mosques.

Ihsan Bagby, Associate Professor at the University of Kentucky, provided location information for each of these mosques to the U.S. Religion Census data collection office and relied on survey information to estimate a total Muslim population within each state. The U.S. Religion Census staff then used Bagby's state-by-state figures to estimate adherents and attendance for each mosque. For surveyed mosques, the reported adherent and attendance counts were used. For those not surveyed, the remaining state Muslim counts were assigned proportionately, with larger estimates for those mosques within larger metropolitan areas. Totals were then aggregated to the county level.

A total of 2,106 mosques were identified, representing a 74 percent increase over the 1,209 counted in 2000. Though the increase can be attributed partly to improved web sites and data collection, it also reflects real growth in the Muslim population. Twenty-six percent of all the mosques studied were established between 2000 and 2011.

Buddhist and Hindu Counts

J. Gordon Melton provided the Religion Census data collection office with a list of 215 Buddhist groups in 2,854 locations. Constance A. Jones and J. Gordon Melton provided a list of 127 Hindu groups with 1,625 locations. In most cases, a total number of persons associated with each group was included. The number of persons associated with specific locations was often available. For groups or locations without identified totals, estimates were made based upon similar groups or locations. After these allocations, the total numbers of adherents reported in the earlier tables may differ slightly from the figures originally reported in the accompanying text.

Non-Denominational Churches

Over the past several years, Scott Thumma, Professor of Sociology of Religion at the Hartford Institute for Religion Research, has been collecting non-denominational church lists available on the Internet. To this list were added eight additional listings of non-denominational congregations, house churches, megachurches and independent networks of churches that were collected on the Web and privately during 2009-2010. Additionally, three purchased mailing lists of independent and non-denominational Christian congregations were added to the database. After all these lists were merged together, the database was then screened for duplicates, incorrect entries, and non-church listings.

Following this effort, a team of six temporary staff persons spent more than 1,000 hours culling the web to attempt to verify the status of these congregations. Every church in the database was looked up on Google and in the online Yellow Pages to confirm if it existed and if it was independent/nondenominational. Every church was emailed and/or called in order to further confirm its independent/non-denominational status, membership and attendance. Additionally, one of the staff members spoke Spanish and established contact with the obviously Hispanic/Latino churches in the listing. Approximately 30 percent responded to the request and verified their information. While engaged in this research, the staff found additional church lists from the websites of newspapers, towns and counties that added new independent and non-denominational churches. They then attempted to confirm the information on these churches using the above method. The end result was a database that contained more than 50,000 potential entries. More than 15,000 were removed due to uncertainty about their existence, size, non-denominational status or being a part of the Vineyard Christian Fellowship or Calvary Chapel networks (which are listed separately in the 2010 U.S. Religion Census). The resulting 35,496 congregations are the best estimate of the independent and non-denominational churches in the United States.

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