Software Engineering | W-Model

Paul Herzlich introduced W-Model in 1993.

W-model is the most recent software development model where we start real testing activity simultaneously software development process starts. Where as software development process is a method in which a software or product is made through various stages of planning, development and testing before the final software or product is delivered. testing is such a stage that is extremely crucial to ensure the delivery of an optimum quality product.


  • V-model and W-model are two of the most important models that are used in software testing.
  • W-Model covers those activities which are skipped by V-Model and also, it deals with problems which couldn’t be catch by V-Model.
  • W-Model approach attempts to address and tackle the shortcomings W-Model approach attempts to address and tackle the shortcomings of V-Model.
  • W-model can be done only once the development of the product is complete with no modifications required to be done in between. This type of testing is most suitable for short projects.
  • With the help of W-Model, we ensure that the testing of the product starts from the very first day of the inception of product and each phase of the product development is verified and validated.

Phases of W-Model:
Each phase is verified/validated. Dotted line shows that every phase in green is validated/tested through every phase in sky blue. Now, in the above figure,