It was something I had heard repeated as long as I had been in ministry: "85 percent of all people who accept Christ do so before the age of 18." I was never exactly clear where that statistic came from, but I had no reason to doubt it either. Everyone I knew considered it an evangelistic axiom.
The good part of the statistic was that it reinforced the importance of reaching children and youth with the gospel. They are receptive. Important decisions are made before adulthood. And we must reach our young people with the gospel.
However, when I made the transition from ministry with students to adults, I quickly saw the downside of the statistic. Now I wanted to help adults reach their friends and neighbors for Christ. Though most were willing to try, I could see they didn't have much expectancy. They assumed that once people got past a certain age (the axiom indicated it was 18) the odds of them responding to the gospel were dismal.
At my first church, I remember encouraging board members in their personal evangelism. I asked them with whom they were sharing their faith. Marvin spoke up. He was one of my most supportive leaders, but he didn't sound very hopeful: "Well, pastor, I've been talking with Jim who works next to me down at the shop. He just split up with his wife and has been asking some questions. He's pushing fifty, though, and pretty set in his ways. I know the chances of him changing now aren't very likely. But I keep praying for him anyway."
I couldn't help but wonder: Was it really that dismal? Does "85 percent of all people who accept Christ do so before the age of 18" mean that it's doubtful that many adults will make a life-changing decision to follow Jesus?
I could understand if someone was raised with faith, they would likely make up their mind before they left home, but what about someone who didn't have that advantage? Were the odds forever stacked against them?
Interestingly, what I was seeing in my own ministry didn't match up with that. I was watching unchurched people at every stage of life respond to the gospel. Were these just anomalies to the pattern, or was there something more?
It wasn't merely a theoretical question for me. My life, my calling, was about reaching people for Christ in a culture increasingly distanced from the gospel, the church, and all things Christian. So I set out to find answers.
Search and Research
I'm a pastor, not a researcher, but with the assistance of two sociologists from Oregon State University, I decided to test the "85/18 Rule." I wanted to know when, why, and how those not raised in the church come to faith in Christ.
I decided to talk to people who had accepted Christ as adults and stuck. I didn't want to try to figure out what it meant when someone walked down an aisle but then never came back. I didn't want to decide how to categorize people who said they believed certain propositions about Jesus but didn't actually practice their faith. I wanted to find people who had decided to follow Christ and remained active in their faith and church—the exact kind of disciple I would be hoping for if I led someone to Christ.
I found lots of people like that in evangelical churches across the country who were willing to share their stories. They worshipped in rock-and-roll megachurches and quiet roadside chapels. They lived out their faith in little towns in Wisconsin and sprawling cities of Southern California. Eventually, through surveys, personal interviews, and statistical analysis, I compared the faith experiences of more than 3,000 believers from 31 states and a dozen denominations.