But a new study questions this prevailing wisdom. Claims that losses in old-line denominations are more than offset by gains in evangelical denominations . In addition to the fact that evangelical gains simply are not numerically large enough, Americans in declining denominations still claim high levels of membership and attendance. It has long been known that people tend to make themselves look better than they are in surveys. Many people, for example, tell pollsters that they vote regularly, although their names are absent from voting records.
Many youths underreport deviant behavior, such as substance abuse.
First they did a poll, then they did a head count. Then they compared the polls to the pews. To be as accurate as possible, the authors located every single church in the county, driving the length of every road. Some congregations were counted physically, and average attendance counts were received from other churches through denominational yearbooks, telephone interviews, and letters. Marwell pointed out that the ASR study was reviewed before publication by a panel of noted sociologists.