In selecting the appropriate approach, the complexity of the project should be taken into consideration. Such factors,
- number of stakeholders
- number of business areas impacted
- number of business systems impacted
- amount and nature of risk
- uniqueness of requirements
- number of technical resources required
Some projects, such as government projects or projects where the final product carries a high risk if produced incorrectly (e.g. pharmaceuticals and aircraft), require a high level of control and documentation. Because documentation and control are strengths of the waterfall approach, it will better lend itself to supporting such projects.
Note that the level of rigor used should be appropriate to the specific project. If more rigor is applied to a project than required for the project characteristics, there is a risk that additional time and money will be spent that is not needed.
There are additional factors that should be weighed when planning the approach that will be taken during business analysis:
Corporate culture/environment/history
The corporate culture and environment will have a major impact on the approach chosen. If the organization’s process requires either a Waterfall or Agile approach, it will be difficult to change the organization’s mindset,
Level of uncertainty in requirements
Agile methodologies, by design, are designed for the evolutionary uncovering of requirements. As such, they are suitable for projects where the level of requirements uncertainty and the probability of requirements change are high. Waterfall methodologies can work well where the requirements uncertainty is lower.
The level of requirements uncertainty is partly dependent on the subject domain of the project. For example, marketing and research projects tend to have a higher requirements uncertainty, while accounting and finance projects tend to have a relatively lower level of requirements uncertainty.
Length of project/turnover of personnel
The length of a project can affect the approach chosen. In general, the longer the project continues, the greater the likelihood there will be some level of personnel turnover. Under such circumstances, increased documentation is desirable in order to ensure project knowledge and minimize ramp-up time for new project members in the later project stages. Waterfall is more likely to provide the needed level of documentation required for knowledge transfer than Agile.
