Yearbook of American and Canadian Churches 2010 - Cokesbury

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PERSPECTIVES ON AMERICA’S
RELIGIOUS LANDSCAPE
Trends & Developments, 2009
TRENDS &
DEVELOPMENTS, 2009
Methodological Considerations
The Yearbook of American & Canadian Churches reports annually on data gathered
from national religious bodies that reflect the religious affiliations and financial giving
patterns of hundreds of millions of Americans. However, these data generally represent
information gathered two calendar years prior to the year of publication. For instance, data
reported in this 2010 edition of the Yearbook reflects information for 2008 that was collected
by national church structures in 2009 and reported to the Yearbook at the end of
2009 for publication in this 2010 Yearbook. This “lag time” often leads our readers to ask
if such data is out of date by the time it is printed. In response we would give a qualified
“no.” Massive national agencies such as the churches reporting through the Yearbook
move in their institutional lives at nearly imperceptible rates of speed. Moreover, given
the vast size and complexity of such diverse organizations, partial data reported more frequently
might well have the unintended effect of conveying a sense of “trend” to momentary
or regionally isolated patterns of reporting, affiliation and/or financial giving. Now in
the 78th edition, the Yearbook believes that an annual review of data continues to provide
an appropriate interval for tracking the changes in institutional patterns.
No single standard for data collection exists across the variety of ecclesiastical structures
reported in the Yearbook. Moreover, the definitions of membership and related terms
differ widely from one church structure to another. This lack of universal definition and
collection methodology has frequently led to questions about the validity and reliability
of self-reported data. Recognizing the limitations of the data reported herein, we continue
to have confidence in the overall value of trends and other findings based on these figures
and this methodology. While church data collection and analytical practices differ across
various institutional and organizational margins, they tend to be remarkably consistent
within specific organizations over time. (Where we are made aware of changes in a particular
church’s reporting methods, we will note them for the reader.) This consistency
within organizations brings a greater degree of confidence to the relative data of a given
church over time. For the same reason the relative size of one church to another as
reported here, we believe, provides an accurate picture even while lacking a degree of
absolute precision of membership statistics, particularly over time. Thus, we believe that
the Southern Baptist Convention is roughly twice the size of The United Methodist
Church, for example, and that changes relative to each other over several years are probably
an accurate reflection of actual membership trends. Moreover, these data are the most
exacting figures presently available, and thus serve as the national standard.
The first eight decades of record keeping represented by the Yearbook of American &
Canadian Churches is contained on a comprehensive Historic Archive on CD-ROM
(which contains membership and financial data from 1916–1999). This CD provides a
longitudinal backdrop for the analysis that follows. Only through such a longitudinal
study of growth and decline in membership are we able to capture and analyze the
emerging patterns. Our annual trends analysis should be regarded as a snapshot taken at
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