What is Impact Analysis
From Requirements Management School
Impact analysis forms part of the review stage of the change control process.
It is a formal approach that is adopted to identify any possible risks associated with a change request. It is a process that is generally carried out by the development team.
The analysis only takes place once the change request has been initially reviewed by the change control board. This is because analysis impact takes up a considerable amount of resource (time).
Impact analysis should only be carried out by personnel with in-depth knowledge of the project (such as engineering leads, project managers, et al) to ensure that nothing is missed. It is highly preferable to use requirements management tools such as Accompa - such tools can reduce the time needed to perform impact analysis (often by a significant amount), while improving accuracy.
Why Perform Impact Analysis?
Implementing an impact analysis as part of your change control process is the sensible course of action because many major incidents that occur during a project can be directly traced back to the change control process.
However, please note that Impact Analysis is not a magic wand - it simply minimizes the possibility of major issues arising when implementing changes during a software engineering project.
How to Perform Impact Analysis
The impact analysis is a fairly simple process that can be carried as a checklist, using a word processor or a spreadsheet. It consists of three stages:
- In-depth investigation to define the extent of the proposed change – this includes defining the extent of the request and the impact that it will have on the baseline and other pending change requests. A holistic view is taken of the project in order to confirm all dependencies that are affected; the consequences of making the changes; the risks associated with the implementation; and the effect on the resources already allocated for the project. Taking into account cost, time and quality implications.
- Identification of all the tasks needed to effect the change – once the first stage has been established an analysis of the actual changes needed in order to implement the change request are investigated.. This means going through and identifying all the changes needed to the user interface; design components; source code; hardware; databases and files; build files; test cases, use cases; documentation; and any further resources that may need to be purchased.
- Analysis of the resources required to implement the change – once all the data is gathered in stages one and two a detailed estimate must be made of the effort required to implement the change, time and costs; together with an evaluation of whether or not the change falls within the projects critical path.
The impact analysis is then referred to the change control board that use it to come to a well-informed opinion of whether or not the change request should be authorized or rejected.
