Paul Herzlich introduced the W-Model approach in 1993. The W-Model attempts to address shortcomings in the V-Model. Rather than focus on specific dynamic test stages, as the V-Model does, the W-Model focuses on the development products themselves. Essentially, every development activity that produces a work product is shadowed by a test activity. The purpose of the test activity specifically is to determine whether the objectives of a development activity have been met and the deliverable meets its requirements. In its most generic form, the W-Model presents a standard development lifecycle with every development stage mirrored by a test activity. On the left hand side, typically, the deliverables of a development activity (for example, write requirements) is accompanied by a test activity test the requirements and so on. If your organization has a different set of development stages, then the W-Model is easily adjusted to your situation. The important thing is this: the W-Model of testing focuses specifically on the product risks of concern at the point where testing can be most effective.