Here's an excerpt to generate your interest in the article at the Barna website.
The lives of Captive Christians are defined by their faith; their worldview is built around their core spiritual beliefs and resultant values. Casual Christians are defined by the desire to please God, family, and other people while extracting as much enjoyment and comfort from the world as possible. The big difference between these two tribes is how they define a successful life. For Captives, success is obedience to God, as demonstrated by consistently serving Christ and carrying out His commands and principles. For Casuals, success is balancing everything just right so that they are able to maximize their opportunities and joys in life without undermining their perceived relationship with God and others. Stated differently, Casuals are about moderation in all things while Captives are about extreme devotion to their God regardless of the worldly consequences.