Editing Porter's five forces analysis (section)

== Criticisms ==
Porter's framework has been challenged by other academics and strategists. For instance, Kevin P. Coyne and Somu Subramaniam claim that three dubious assumptions underlie the five forces:
* That buyers, competitors, and suppliers are unrelated and do not interact and [[collusion|collude]].
* That the source of value is a structural advantage (creating barriers to entry).
* That uncertainty is low, allowing participants in a market to plan for and respond to changes in competitive behavior.<ref>Kevin P. Coyne and Somu Subramaniam, "Bringing Discipline to Strategy, ''[[McKinsey Quarterly]]'', 1996, (Vol. 33, No. 4), pp. 14–25.</ref>

An important extension to Porter's work came from Adam Brandenburger and [[Barry Nalebuff]] of [[Yale School of Management]] in the mid-1990s. Using [[game theory]], they added the concept of [[complementors]] (also called "the 6th force") to try to explain the reasoning behind strategic alliances. Complementors are known as the impact of related products and services already in the market.<ref>Brandenburger, A. M., & Nalebuff, B. J. (1995). The Right Game: Use Game Theory to Shape Strategy. ''[[Harvard Business Review]]'', (Vol. 73, No. 4), 57–71. [https://spinup-000d1a-wp-offload-media.s3.amazonaws.com/faculty/wp-content/uploads/sites/8/2019/06/RightGame_HBR1995.pdf PDF]</ref> The idea that complementors are the sixth force has often been credited to [[Andrew Grove]], former CEO of [[Intel Corporation]]. Martyn Richard Jones, while consulting at [[Groupe Bull]], developed an augmented five forces model in Scotland in 1993. It is based on Porter's Framework and includes Government (national and regional) as well as pressure groups as the notional 6th force. This model was the result of work carried out as part of [[Groupe Bull]]'s Knowledge Asset Management Organisation initiative.

Porter indirectly rebutted the assertions of other forces, by referring to innovation, government, and complementary products and services as "factors" that affect the five forces.<ref name=":1">Michael E. Porter. "The Five Competitive Forces that Shape Strategy", ''[[Harvard Business Review]]'', January 2008 (Vol. 88, No. 1), pp. 78–93. [http://hbr.org/2008/01/the-five-competitive-forces-that-shape-strategy/ar/1 PDF]</ref>

It is also perhaps not feasible to evaluate the attractiveness of an industry independently of the resources that a [[firm]] brings to that industry. It is thus argued (Wernerfelt 1984)<ref>Wernerfelt, B. (1984), A Resource-based View of the Firm, ''[[Strategic Management Journal]]'', Vol. 5: pp. 171–180 [http://web.mit.edu/bwerner/www/papers/AResource-BasedViewoftheFirm.pdf PDF]</ref> that this theory be combined with the [[Resource-based view|resource-based view (RBV)]] in order for the firm to develop a sounder framework.

Other criticisms include:

* It places too much weight on the macro-environment and does not assess more specific areas of the business that also impact competitiveness and profitability<ref name=":4">{{Cite journal|last=Grundy|first=Tony|date=2006|title=Rethinking and reinventing Michael Porter's five forces model|url=http://dx.doi.org/10.1002/jsc.764|journal=Strategic Change|volume=15|issue=5|pages=213–229|doi=10.1002/jsc.764|issn=1086-1718|url-access=subscription}}</ref>
* It does not provide any actions to help deal with high or low force threats (e.g., what should management do if there is a high threat of substitution?)<ref name=":4" />