When there are a several choices of project managing lifecycles to choose from, which one suites you best.
Waterfall approach. Iterative cycles or spiral model. CMMI. Or the German V-Model.
The V-Model is an interesting concept from Germany. The left tail represents specifications; the right tail as the testing stream related to the specifications defined on the left. The V bottom represents the development stream.
Many projects fall short in the testing cycles. Either not enough or not enough of the right kind. The V-Model shows that testing needs to occur at all levels from the developers code to the business requirements.