Originally Published in 2011
The Professor recently received the following question:
Having put together a spreadsheet of information that I need to assess the impact of a change, what I need to do next is figure out how to assess the impact of a change as being high, medium, or low? Any guidance you can give me on how to do this would be greatly appreciated.”The Service Transition book provides great guidance on assessing the impact of changes (ST 220.127.116.11). This section provides 7 questions that must be answered to fully understand the impact. Many of these questions are answered using information in your spreadsheet. Others you may want to consider adding.
- Who RAISED the change?
- What is the REASON for the change?
- What is the RETURN required from the change?
- What are the RISKS involved in the change?
- What RESOURCES are required to deliver the change?
- Who is RESPONSIBLE for the build, test and implementation of the change?
- What is the RELATIONSHIP between this change and other changes?
The Microsoft Operations Framework (MOF) Change and Configuration Service Management Function (Table 6) gives the following guidelines for prioritizing changes based on business impact, urgency and required resources:
- Low. The change can wait until the next scheduled release.
- Medium. Because of its impact level, the change cannot wait until the next scheduled release.
- High. The change needs to be released as soon as it is complete and has been tested.
- Emergency. The change needs to be released as soon as possible; many of the approval and the development steps are abbreviated.
NOTE: If your organization has too many "emergency" and "high priority" changes, this may indicate that staff are avoiding the process or that the process is not effective.
ITIL and MOF also factor in risk when assessing changes and looks at both change impact, and the probability of that impact. For example, a change that has the possibility of high impact and also the probability of high impact will be the highest category of risk. High impact, low probability, the next highest category, and so forth.