Small groups are one of the most advantageous models for churches and most mega-churches are built on that structure, according some church-growth experts.
"There are almost no huge churches today that aren't built on small groups," said John Ellas, director of the Center for Church Growth.
This small-group model is "certainly one factor" for the growth of Saddleback Church in Lake Forest, Calif. -- one of the largest mega-churches with over 30,000 Sunday service attendants -- and there are good reasons why.
According to the website of Purpose Driven Ministries, the dynamics and small size enable every member to connect with the church, cultivate small group leaders and coaches, multiply those serving in volunteer ministires, and make an impact on the community.
"Small Group ministry is the most underestimated and unknown resource available to cultivate the spiritual, numerical, and financial health of your church," a statement from the website read.
Saddleback Pastor Rick Warren, whose best-selling book "Purpose Driven Life" inspired Purpose Driven Ministries, said there are ways to use small groups effectively for evangelism.
First of all, each small group must "care about people who dont know Jesus," Warren wrote on the Purpose Driven website.
He elaborated by describing the miraculous healing of a paralytic in Luke 5. Warren explained that the paralytic was able to be healed because of the love of the four friends who carried him on a stretcher to where Jesus was teaching.
"The reason God used the four friends in Luke 5 is because they cared for the paralytic. Just like those four, the evangelistic mission of your small groups need to start with love," said Warren.
Once the heart is there, Warren explained that small groups must set up plans to put the desire into action. And after the plan comes the willingness to overcome difficulties, he wrote.
"Some people will only come to Jesus through a group effort," said Warren, and studies have shown that a supportive environment is conducive for spiritual growth.
Through these methods, Warren's church grew from a mere 205 people in 1980 to over 30,000 today.
Ellas, meanwhile, believes the small-group model is effective for several reasons, such as its impact on younger leaders who are hungry for relationships.
"They have grown up with no extended family and a fractured nuclear family, so they hunger for genuine relationships," he said of the youth.
Most established churches in America are built on the Sunday School movement where groups of 25-40 sit through lectures. However, according to Ellas, these schools do not meet the needs of the younger generation, and small groups - with face-to-face interactions - are making up for that deficit.
"Churches aren't going to reach young adults in Generation X - people born after 1964 - unless you have meaningful community, and the only way you get meaningful community is face to face interaction," he explained. "They dont want to hear about your faith, they want to experience in it."
Warren believes this experience comes when church leaders and small-group members have a willingness to sacrifice their own comfort to bring a friend to Jesus.
"These four men wouldnt have made a hole in the roof unless they were willing to fix it," explained Warren. "They had to pay the cost of bringing their friend to Jesus."