While the United States remains shaped by Christianity, the faith’s influence—particularly as a force in American politics and culture—is slowly waning. An increasing number of religiously unaffiliated, a steady drop in church attendance, the recent Supreme Court decision on same-sex marriage, and the growing tension over religious freedoms all point to a larger secularizing trend sweeping across the nation.

But how do the numbers stack up? Is America, home to the largest Christian population in the world, actually becoming a “post-Christian” nation? In a recent study, Barna Group analyzed 60,808 interviews conducted over a seven-year period to measure irreligion in American cities. Currently, 78% of Americans describe themselves as “Christian,” but in order to dig deeper than just self-affiliation, Barna Group looked at a variety of key faith indicators for both belief and practice.

To measure a person’s level of irreligion, Barna Group tracks 15 metrics related to faith (you can find the full list of 15 at the end of the article). These factors speak to the lack of Christian identity, belief and practice. These factors include whether individuals identify as atheist, have never made a commitment to Jesus, have not attended church in the last year, or have not read the Bible in the last week.

These kinds of questions—compared to ticking the “Christian” box in a census—get beyond how people loosely identify themselves (affiliation), and get to the core of what people actually believe and how they behave as a result of their belief (practice). These indicators give a much more accurate picture of belief in America.

To qualify as “post-Christian,” individuals had to meet 60% or more of the factors (nine or more out of 15 criteria). “Highly post-Christian” individuals meet 80% or more of the factors (12 or more of these 15 criteria). Read more about Barna’s post-Christian metric.

Where Are We as a Nation?

Whether one believes this decline of “Christian America” calls for a time of lament, or presents great opportunity (or both) for the church, one cannot help but accept the changing landscape. In just two years, the percentage of Americans who qualify as “post-Christian” rose by 7 percentage points, from 37% in 2013 to 44% in 2015. Across the United States, cities in every state are becoming more post-Christian—some at a faster rate than others.

Read the article.