Appendix A - Methodology

Methodology

Throughout this book we refer to primary research that is not footnoted. These statistics and data-based analyses are derived from a series of national public-opinion surveys conducted by Barna Group.

Once data was collected, minimal statistical weights were applied to several demographic variables to more closely correspond to known national averages. On questions for which tracking was available, findings from these recent studies were compared to Barna’s database of national studies from the past three decades. Data from the clergy study were minimally weighted on denomination and region to more closely reflect the demographic characteristics of churches in each media market.

When researchers describe the accuracy of survey results, they usually provide the estimated amount of “sampling error.” This refers to the degree of possible inaccuracy that could be attributed to interviewing a group of people that is not completely representative of the population from which they were drawn. For the general population surveys, see the table on the next page for maximum sampling error.