A business analysis plan outlines the business analysis activities that will be performed to fulfill overall project goals.
A good business analysis plan states the outcome, activities, techniques, deliverables, and risks.
The outcome states what will be gained from executing the business analysis plan. Most often the outcomes are a better understanding of different areas of a domain.
The activities state what is going to be done, who is involved, when the activities will take place, and how much time is involved.
The techniques explain the different business analysis techniques that will be used within the activities. Often there are multiple techniques that are used.
Deliverables outline the written documents, models, and other artifacts that will be produced. It is important that the deliverables are well thought out and organized. On their own, they should satisfy the outcomes of the business analysis plan. The deliverable also indicates how the deliverables will be communicated to the client including whether they require sign-off.
Risks identify assumptions, the effectiveness of the deliverables, the quality of the deliverables, and potential consequences based on the deliverables. There is always a balance between the risks of missing information and how much time is spent on business analysis activities.
One advantage of the business analysis plan is that the client sees what the understanding was before the plan was executed and the understanding afterward. The client also sees the activities and the time required for the activities. It is easy to forget how much work went into uncovering a well-thought-out solution, especially when there was the complexity that was unraveled into something more elegant.