V-model

[2] The V-model summarizes the main steps to be taken in conjunction with the corresponding deliverables within computerized system validation framework, or project life cycle development.

The easiest way is to say that verification is always against the requirements (technical terms) and validation is always against the real world or the user's needs.

[12] There is no single definition of this model, which is more directly covered in the alternative article on the V-Model (software development).

Its scope is a narrower systems development lifecycle model, but far more detailed and more rigorous than most UK practitioners and testers would understand by the V-model.

The PMBOK guide, also adopted by the IEEE as a standard (jointly maintained by INCOSE, the Systems engineering Research Council SERC, and IEEE Computer Society) defines them as follows in its 4th edition:[17] The V-model provides guidance for the planning and realization of projects.

it is still the standard for German federal administration and defense projects, as well as software developers within the region.

The concept of the V-model was developed simultaneously, but independently, in Germany and in the United States in the late 1980s: It has now found widespread application in commercial as well as defense programs.

All iteration is along a vertical line to higher or lower levels in the system hierarchy, as shown in the figure.

The V-model, while rigid in process, can be very flexible in application, especially as it pertains to the scope outside of the realm of the System Development Lifecycle normal parameters.