The fit-gap document is the primary input document to write the FDD. It is imperative to review the fit-gap document in detail before starting with the FDD. The following are a few pointers to take note of when conducting a successful fit-gap review session:

• The fit-gap review session should involve the functional and technical solution architects, project managers, and customer Subject Matter Experts (SMEs).
• It is important to remember that this is a fit-gap session, so the fit should also be analyzed. Any degree of customization identified in the fit should be recorded.
• Often, you may find gaps listed that aren't really gaps, as the solution can handle the requirement. The review session should discuss each requirement in detail and consider all possible alternate solutions.

• All gaps should be recorded and assigned a unique number. The Microsoft LCS business modeler tool enables you to document your business processes and record gaps.
• Take a detailed look at how the gaps are going to be addressed. Outline the testing/review process for customizations/extensions and how the testing will be administered.
• By focusing on these topics, you will soon learn where the team stands with regard to the appropriate documentation and its approach to the customization process.

Now, in the next heading, let's gets back to the FDD. Why is it necessary, and what purpose does it serve?