A new study by The Barna Group (Ventura, California) shows that despite strong levels of spiritual activity during the teen years, most twentysomethings disengage from active participation in the Christian faith during their young adult years – and often beyond that. In total, six out of ten twentysomethings were involved in a church during their teen years, but have failed to translate that into active spirituality during their early adulthood.

The big question, and I really covet your view (esp if you have experience with this age group): What to do?
Half of teens attend a church-related service or activity in a typical week. More than three-quarters discuss matters of faith with peers and three out of five teens attend at least one youth group meeting at a church during a typical three month period. One-third of teenagers say they participate in a Christian club on campus at some point during a typical school year.
BUT:
The research shows that, compared to older adults, twentysomethings have significantly lower levels of church attendance, time spent alone studying and reading the Bible, volunteering to help churches, donations to churches, Sunday school and small group involvement, and use of Christian media (including television, radio and magazines).
In fact, the most potent data regarding disengagement is that a majority of twentysomethings – 61% of today’s young adults – had been churched at one point during their teen years but they are now spiritually disengaged (i.e., not actively attending church, reading the Bible, or praying). Only one-fifth of twentysomethings (20%) have maintained a level of spiritual activity consistent with their high school experiences. Another one-fifth of teens (19%) were never significantly reached by a Christian community of faith during their teens and have remained disconnected from the Christian faith.
Now for the emerging part:
Loyalty to congregations is one of the casualties of young adulthood: twentysomethings were nearly 70% more likely than older adults to strongly assert that if they “cannot find a local church that will help them become more like Christ, then they will find people and groups that will, and connect with them instead of a local church.” They are also significantly less likely to believe that “a person’s faith in God is meant to be developed by involvement in a local church.”
These attitudes explain other anomalies of twentysomething spirituality. Much of the activity of young adults, such as it is, takes place outside congregations. Young adults were just as likely as older Americans to attend special worship events not sponsored by a local church, to participate in a spiritually oriented small group at work, to have a conversation with someone else who holds them accountable for living faith principles, and to attend a house church not associated with a conventional church. Interestingly, there was one area in which the spiritual activities of twentysomethings outpaced their predecessors: visiting faith-related websites.
Now notice the suggestion of Kinnaman:
Kinnaman offered several insights about the data: “Much of the ministry to teenagers in America needs an overhaul – not because churches fail to attract significant numbers of young people, but because so much of those efforts are not creating a sustainable faith beyond high school. There are certainly effective youth ministries across the country, but the levels of disengagement among twentysomethings suggest that youth ministry fails too often at discipleship and faith formation. A new standard for viable youth ministry should be – not the number of attenders, the sophistication of the events, or the ‘cool’ factor of the youth group – but whether teens have the commitment, passion and resources to pursue Christ intentionally and whole-heartedly after they leave the youth ministry nest.”