In “Measuring Evangelicalism: Consequences of Different Operationalization Strategies,” which is featured in the latest issue of the Journal for the Scientific Study of Religion, co-authors D. Michael Lindsay and Conrad Hackett report that depending on how one defines an “evangelical”—based on denominational affiliation, self-classification, or specific religious beliefs—this group’s political impact can vary widely. According to a press release announcing the study:

“In this election year, there is much debate over whether Sen. Obama can shave off enough evangelical votes to carry certain swing states, said Rice’s D. Michael Lindsay, one of the researchers. “That depends a great deal on which poll you are looking at and, more importantly, how the survey defines the evangelical population.”

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“Evangelicals continue to be the most organized constituency of the Republican Party,” Lindsay said. “However, Democrats have made unprecedented efforts to woo religious voters. They won’t win the votes of all evangelicals, but in a tight election year, they don’t have to — only a few are needed. The perception over whether evangelicals are remaining loyal Republicans or are leaning Democratic depends, in great measure, on which survey is being cited. Evangelicals are the most discussed but least defined population among the American electorate.”

Read the executive summary of the report here.