Editing Design (section)

===Rational model===
The rational model was independently developed by Herbert A. Simon,<ref>Newell, A., and Simon, H. (1972) ''Human problem solving'', Prentice-Hall, Inc.</ref><ref name="Simon">Simon, H.A. (1996) [https://books.google.com/books?id=k5Sr0nFw7psC The sciences of the artificial] {{Webarchive|url=https://web.archive.org/web/20131217052045/http://books.google.com/books?id=k5Sr0nFw7psC&printsec=frontcover |date=2013-12-17 }}, MIT Press, Cambridge, MA, USA. p. 111. {{ISBN|0-262-69191-4}}.</ref> an American scientist, and two German engineering design theorists, Gerhard Pahl and Wolfgang Beitz.<ref>Pahl, G., and Beitz, W. (1996) [https://books.google.com/books?id=8fuhesYeJmkC ''Engineering design: A systematic approach''] {{Webarchive|url=https://web.archive.org/web/20131217052518/http://books.google.com/books?id=8fuhesYeJmkC&printsec=frontcover |date=2013-12-17 }}, Springer-Verlag, London. {{ISBN|3-540-19917-9}}.</ref> It posits that:
# Designers attempt to [[Optimization (mathematics)|optimize]] a design candidate for known [[constraint optimization|constraints]] and [[Goal|objectives]].
# The design process is plan-driven.
# The design process is understood in terms of a discrete sequence of stages.

The rational model is based on a [[Rationalism|rationalist philosophy]]<ref name="Brooks" /> and underlies the [[waterfall model]],<ref name=Royce/> [[systems development life cycle]],<ref name=Bourque/> and much of the [[engineering design]] literature.<ref>Pahl, G., Beitz, W., Feldhusen, J., and Grote, K.-H. (2007 ) [https://books.google.com/books?id=qsKNwB2gL5wC Engineering design: A systematic approach] {{Webarchive|url=https://web.archive.org/web/20131217050322/http://books.google.com/books?id=qsKNwB2gL5wC&printsec=frontcover |date=2013-12-17 }}, (3rd ed.), Springer-Verlag, {{ISBN|1-84628-318-3}}.</ref> According to the rationalist philosophy, design is informed by research and knowledge in a predictable and controlled manner.<ref>{{Cite book |last=Mielnik |first=Anna |url=https://suw.biblos.pk.edu.pl/downloadResource%26mId%3D2650996 |title=Under the power of reason |publisher=Krakow University of Technology |access-date=2022-08-27 |archive-date=2022-08-27 |archive-url=https://web.archive.org/web/20220827204829/https://suw.biblos.pk.edu.pl/downloadResource%26mId%3D2650996 |url-status=live}}</ref>

Typical stages consistent with the rational model include the following:<ref>{{Cite journal |last1=Condrea |first1=Ionut |url=https://media.proquest.com/media/hms/PFT/1/MNTnI?_s=zo3qVt0Rq8V3x%2FgZKecWt8ICAzY%3D |title=Elaboration of the initial requirements in the design activities |last2=Botezatu |first2=C. |last3=Slătineanu |first3=L. |last4=Oroian |first4=B. |journal=IOP Conference Series: Materials Science and Engineering |date=February 2021 |volume=1037 |issue=1 |page=012002 |doi=10.1088/1757-899X/1037/1/012002 |bibcode=2021MS&E.1037a2002S |s2cid=234019940|doi-access=free }}</ref>
* Pre-production design
** [[Design brief]]&nbsp;– initial statement of intended outcome.
** [[Analysis]]&nbsp;– analysis of design goals.
** [[Research]]&nbsp;– investigating similar designs in the field or related topics.
** [[Specification]]&nbsp;– specifying requirements of a design for a product ([[product design specification]])<ref>Cross, N., (2006). ''T211 Design and Designing: Block 2'', p. 99. Milton Keynes: The Open University.</ref> or service.
** [[Problem solving]]&nbsp;– [[wikt:conceptualize|conceptualizing]] and [[document]]ing designs.
** [[Presentation]]&nbsp;– presenting designs.
* Design during production.
** [[Product development|Development]]&nbsp;– continuation and improvement of a design.
** [[Product testing]]&nbsp;– ''[[in situ]]'' testing of a design.
* Post-production design feedback for future designs.
** [[Implementation]]&nbsp;– introducing the design into the environment.
** [[Evaluation]] and [[logical consequence|conclusion]]&nbsp;– summary of process and results, including [[constructive criticism]] and suggestions for future improvements.
* Redesign&nbsp;– any or all stages in the design process repeated (with corrections made) at any time before, during, or after production.

Each stage has many associated [[best practices]].<ref>Ullman, David G. (2009) ''The Mechanical Design Process'', Mc Graw Hill, 4th edition {{ISBN|0-07-297574-1}}</ref>

====Criticism of the rational model====
The rational model has been widely criticized on two primary grounds:

# Designers do not work this way&nbsp;– extensive empirical evidence has demonstrated that designers do not act as the rational model suggests.<ref name="Schön 1983"/><ref name="Ralph 2010"/><ref name=Cross/>
# Unrealistic assumptions&nbsp;– goals are often unknown when a design project begins, and the requirements and constraints continue to change.<ref name="Brooks"/><ref>{{cite journal |doi=10.1145/1005937.1005943 |url=http://www.deepdyve.com/lp/association-for-computing-machinery/life-cycle-concept-considered-harmful-WXRCv45NVM |author1=McCracken, D.D. |author2=Jackson, M.A. |title=Life cycle concept considered harmful |journal=ACM SIGSOFT Software Engineering Notes |volume=7 |issue=2 |year=1982 |pages=29–32 |s2cid=9323694 |access-date=2012-03-25 |archive-date=2012-08-12 |archive-url=https://web.archive.org/web/20120812035944/http://www.deepdyve.com/lp/association-for-computing-machinery/life-cycle-concept-considered-harmful-WXRCv45NVM |url-status=live|doi-access=free }}</ref>