U.S. Religion Census collects data on the number of congregations, members, adherents, and attendees. These data are aggregated to the county level for each group participating. Participating groups are welcome to use their own definitions to determine what and/or who is counted. Each group is asked to explain its definitions concerning the items for which they submit data, and to comment on U.S. Religion Census procedures for estimating adherents if the group is not providing adherent figures. Not all groups collect or report all items.
General Guidelines for Defining Congregations, Members, Adherents, and Attendees.
Congregations: Congregations may be churches, mosques, temples, or other meeting places. A congregation may generally be defined as a group of people who meet regularly (typically weekly or monthly) at a pre-announced time and location.
Members: Members are determined by the by-laws of each participating group. Members in Christian Protestant denominations are most often referred to as "full" or "communicant" members.
Adherents: The adherent figure is meant to be the most complete count of people affiliated with a congregation, and the most comparable count of people across all participating groups. Adherents may include all those with an affiliation to a congregation (children, members, and attendees who are not members). If a participating group does not provide the number of adherents, U.S. Religion Census may estimate the number of adherents through the use of a statistical procedure (this will only be done with the approval of the participating group). For groups that report the number of members but not adherents, the general formula for estimating adherents is: Compute what percentage the group's membership is of the county's adult population (14 and older), and then apply that percentage to the county's child population (13 and younger), and then take the resulting figure and add it to the group's membership figure.
Attendees: U.S. Religion Census looks for the number most comparable to an average weekly attendance (or monthly depending on the frequency of the group's meetings) during worship services.
Note: U.S. Religion Census does not collects addresses of individual congregations. This information is only needed if a participating group asks U.S. Religion Census to help determine the county locations of the group's congregations. If congregation addresses are submitted in order to determine county location, U.S. Religion Census promises not to redistribute or sell the address information in any way, shape, or form.