The “one board” model is based on the work of John Edmund Kaiser, who wrote Winning on Purpose: How to Organize Congregations to Succeed in Their Mission. Kaiser’s work has been expanded upon by consultants Kay Kotan and Blake Bradford in their book Mission: Possible.
The basic premise: Congregations are most effective at nurturing current disciples, reaching new disciples, and engaging in transformational ministry when the leadership structure includes RESPONSIBILITY, AUTHORITY, and ACCOUNTABILITY. If any of these pieces is missing, energy is expended on things other than accomplishing the mission of the congregation. The goal: Having a leadership structure that is both safe and effective for supporting ministry.