Editing V-model (section)

{{Short description|Graphic of a systems development lifecycle}}
{{For|the version specific to software development|V-model (software development)}}
[[Image:Systems Engineering Process II.svg|thumb|420px|The V-model of the systems engineering process.<ref name="FHWA 05">[http://www.itsdocs.fhwa.dot.gov/jpodocs/repts_te/14158.htm ''Clarus Concept of Operations''] {{Webarchive|url=https://web.archive.org/web/20090705102900/http://www.itsdocs.fhwa.dot.gov/jpodocs/repts_te/14158.htm|date=2009-07-05}}, Publication No. FHWA-JPO-05-072, Federal Highway Administration (FHWA), 2005.</ref>]]
{{Software development process}}

The '''V-model''' is a graphical representation of a [[systems development lifecycle]]. It is used to produce rigorous development lifecycle models and project management models. The V-model falls into three broad categories, the German ''V-Modell'', a general testing model, and the US government standard.<ref>[http://www.clarotesting.com/page11.htm#coherence "The Dangerous & Seductive V Model"] {{Webarchive|url=https://web.archive.org/web/20190915230955/http://www.clarotesting.com/page11.htm |date=2019-09-15}}, accessed January 9, 2013.</ref>

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. It describes the activities to be performed and the results that have to be produced during product development.

The left side of the "V" represents the decomposition of requirements, and the creation of system specifications. The right side of the "V" represents an integration of parts and their validation.<ref name="VPM" /><ref name="INCOSE" /><ref>{{cite journal|year=1998|title=System Engineering for Faster, Cheaper, Better|url=http://www.incose.org/sfbac/welcome/fcb-csm.pdf|publisher=Center of Systems Management|author=Forsberg, K., Mooz, H.|archive-url=https://web.archive.org/web/20030420130303/http://www.incose.org/sfbac/welcome/fcb-csm.pdf|archive-date=April 20, 2003}}</ref><ref>{{cite web|url=http://www.gmu.edu/departments/seor/insert/robot/robot2.html|title=The SE VEE|publisher=SEOR, George Mason University|access-date=May 26, 2007|archive-url=https://web.archive.org/web/20071018220159/http://www.gmu.edu/departments/seor/insert/robot/robot2.html|archive-date=October 18, 2007|url-status=dead|df=mdy-all}}</ref><ref name="Original">Forsberg, K. and Mooz, H., [http://www.csm.com/repository/model/rep/o/pdf/Relationship%20of%20SE%20to%20Proj%20Cycle.pdf "The Relationship of Systems Engineering to the Project Cycle"] {{Webarchive|url=https://web.archive.org/web/20090227123750/http://www.csm.com/repository/model/rep/o/pdf/Relationship%20of%20SE%20to%20Proj%20Cycle.pdf |date=2009-02-27 }}, First Annual Symposium of the National Council On Systems Engineering (NCOSE), October 1991</ref> However, requirements need to be validated first against the higher level requirements or user needs. Furthermore, there is also something as validation of system models. This can partially be done on the left side also. To claim that validation only occurs on the right side may not be correct. 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. The aerospace standard RTCA [[DO-178B]] states that requirements are validated—confirmed to be true—and the end product is verified to ensure it satisfies those requirements.

Validation can be expressed with the query "Are you building the right thing?" and verification with "Are you building it right?"