My understanding of what it means to live the Christian life is described in the unpublished book Enjoying God. Our ministry should result in measurable, graphable church growth. This is the basically the Sunday School class, although I have worked with some home groups. Most of what it means to be a church happens in the small group. I evaluate my success primarily on the basis of Sunday School attendance.
Groups can double every two years or less if they are properly organized and functioning.
Every member should seek to use their gift to grow their group. You Can Double Your Class in Two Years or Less. As these growing groups get together, they will need larger and larger facilities in order to meet corporately for worship. I believe the multi-congregation approach is the most practical way of meeting this need. By this I mean offering multiple services at various times.