All project management methodologies have one thing in common, the need for a viable business case.  If a viable business case does not exist then the project should not be started.  Similarly, if that justification becomes invalid during the course of the project, the project should be stopped.

In a Prince2 project the business case provides:

·         The driving force behind project

·         Justification for the start and continuation of the project

·         Focus on totality of business change

A Business Case is a description of the reasons for the project and the justification for undertaking the project, based on the estimated costs of the project, the risks and the expected business benefits and savings.

Prince2 doesn't define the exact format of the business case - this will be a standard within organisations, although Appendix A of the manual gives a suggested outline. Any business case should contain at least the following sections:

·         The reasons for the project, which should include some supporting background information, both historical and operational

·         An appraisal of the different options to achieve the business benefit, and the reasons for the preferred option

·         In almost all projects the option of doing nothing should be included with the costs and risks of inactivity included along with the differences (costs, risks, outcomes etc) between doing nothing and the proposed project.

·         The preferred option should always be last on the list

·         All options should be given equal billing; however some additional justification can be given for the preferred option if required.  For example, the preferred option is $5000 more expensive than any of the others, but does include 3 years on site maintenance.

·         Identification of the tangible and intangible benefits

·         Identification of the tangible and intangible dis-benefits

·         An appraisal of the risks involved

·         An analysis of the expected costs and timescales

·         An Investment Appraisal.

If there is no outline business case in the project mandate there needs to be one included with the project brief.  The business case is refined as part of Initiating a Project and becomes part of the Project Initiation Document (PID).

The business case is a dynamic element of the PID because just like plans and risks it is going to change.  After project start up and initiation the business case needs to be reviewed and updated during Managing Stage Boundaries, during Controlling a Stage when analysing the impact of issues, and during Closing a Project to help with the post-project review planning.

The key question to ask when reviewing or updating the business case is always ' Do we still have a viable and worthwhile project?' As a result of this regular review and updating the project may be terminated or future parts modified. The business case may also be subject to amendment if the review concludes that the business need has decreased or changed.