The Institute of Internal Auditors (The IIA)

Converting from old to new computer systems is an important, but often underestimated, aspect of IT projects. Implementing a new system usually requires a variety of system changes, production data conversion and migration, and new operational policies and procedures. Each of these areas poses significant risk to the organization during the actual system conversion. Consequently, conversion audit efforts typically focus on reviewing plans and results for:

1. The overall implementation of the IT solution.
   
2. The systems that are required to implement the IT solution.
   
3. The operational changes required within the organization as part of the implementation.

When planning system conversion audits, auditors need a good understanding of the business requirements for the system, the project's risks, and how the proposed system will work. To understand the solution, they must identify the various operational and system changes that will be implemented. Also, because project information usually becomes available over time, some audit planning will have to be completed on an iterative basis. [...]
[CLB: Terrific overview of auditor's responsibilities.]