Advantages of the W-Model
In the W-model the importance of the tests and the ordering of the individual activities for testing are clear. Parallel to the development process, in a tighter sense, a further process - the test process - is carried out. This is not first started after the development is complete.
The strict division between constructive tasks on the left-hand side and the more destructive tasks on the right-hand side that exists in the V-model is done away with. In the W-model it is clear that such a division between tasks is not sensible and that a closer co-operation between development and testing activities must exist. From the project outset onwards the testers and the developers are entrusted with tasks and are seen as an equal-rights partnership. During the test phase, the developer is responsible for the removal of defects and the correction of the implementation. The early collaboration and the tight co-operation between the two groups can often in practice avoid conflict meetings.
The W-model becomes closer to practice when the test expenditure is given 40% and more. The model clearly emphasises the fact that testing is more than just construction, execution and evaluation of test cases.