Rumelt vs Porter: What Strategy Is, and How Each Tells You to Build One
A comparison of Richard Rumelt's strategy kernel and Michael Porter's five forces and trade-offs: where they differ, what each is for, and how to use them together.
Two names dominate how people talk about strategy: Michael Porter, whose five forces appear in nearly every business school, and Richard Rumelt, whose Good Strategy/Bad Strategy became a favorite of executives tired of strategy decks. People compare them because they seem to describe different activities under the same word.
What is the core difference?
Porter asks what shapes profitability in an industry and where a company can stake out a defensible position. His work is analytical. It gives you a way to read the forces around you.
Rumelt asks what a good strategy document actually contains and why most do not. His work is diagnostic and practical. It gives you a test for whether a plan is strategy at all.
One looks outward at structure. The other looks at the quality of the thinking that produces a plan.
What does Porter say?
Michael Porter's Competitive Strategy (1980) set out the five forces: rivalry among existing competitors, the threat of new entrants, the threat of substitutes, and the bargaining power of buyers and suppliers. Competitive Advantage (1985) added the value chain and the generic strategies of cost leadership, differentiation, and focus.
His 1996 Harvard Business Review article What Is Strategy? argues that strategy is about choosing a unique position and making trade-offs, and that activities should fit together so that the whole is hard to imitate. He distinguishes strategy from operational effectiveness, which is performing similar activities better than rivals.
What does Rumelt say?
Richard Rumelt's Good Strategy/Bad Strategy (2011) argues that much of what organizations call strategy is bad strategy. He names recurring signs: fluff, avoiding the challenge, mistaking goals for strategy, and setting objectives that do not follow from the situation.
His alternative is the kernel. A diagnosis names the nature of the challenge. A guiding policy chooses an overall approach to deal with it. Coherent actions are the steps that carry it out. He also stresses concentrating resources on a pivotal objective rather than spreading effort thin.
How do they compare?
| Dimension | Rumelt | Porter |
|---|---|---|
| Central question | Does this plan deal with a specific challenge? | What shapes returns in this industry and position? |
| Core tool | Kernel: diagnosis, guiding policy, coherent actions | Five forces, value chain, generic strategies |
| Direction of attention | Inward and practical: the quality of the plan | Outward and analytical: structure and position |
| What counts as bad | Fluff, goals presented as strategy | Competing on operational effectiveness alone |
| Role of choice | Focus resources on a pivotal objective | Make trade-offs and decide what not to do |
| Best known for | Good Strategy/Bad Strategy (2011) | Competitive Strategy (1980), What Is Strategy? (1996) |
When does each one fit?
Porter's frameworks fit when you need to understand an industry: entering a market, assessing a competitor, or judging whether margins are likely to hold. They give you a vocabulary for pressure and a way to compare positions.
Rumelt's kernel fits when you have a plan and are not sure it is strategy, or when a team is stuck choosing between many priorities. Writing a diagnosis that rules things out forces clarity quickly.
Where the industry is unclear, Rumelt's approach has less to work with. Where the plan is unclear, Porter's analysis will not write it for you.
What does this look like in practice?
Consider a regional software firm selling to hospitals. A Porter analysis would show powerful buyers, a few large suppliers of data, and incumbent rivals with deep integrations. That is a useful, sober picture of where margin gets squeezed.
Rumelt's question comes next: what is the actual challenge? Perhaps it is that hospitals buy on integration with their existing systems, where the firm is weak. The guiding policy might be to compete only in departments that run standalone, and the coherent actions would follow from that. Without the diagnosis, the analysis stays a report. Without the analysis, the diagnosis may rest on a poor reading of the market.
"Here is my current strategic plan: [paste]. Apply Rumelt's test: does it contain a diagnosis, a guiding policy, and coherent actions? Identify any parts that read as goals, slogans, or lists of priorities. Then, using Porter's idea of trade-offs, tell me what the plan implies we will choose not to do, and whether that is stated."
Why it works: the two tests look at different weaknesses, so a plan that passes one can still fail the other.
Can you use both together?
Naturally. Porter's analysis can feed a diagnosis: the five forces show that buyers hold most of the power, and that becomes part of Rumelt's statement of the challenge. The kernel then turns the analysis into a guiding policy and actions.
A common failure is stopping after the analysis and calling it strategy. A report on forces is an input, not a plan.
"Here is my industry analysis using the five forces: [paste]. Using Rumelt's kernel, help me write three possible diagnoses of the core strategic challenge in one sentence each. For each, suggest a guiding policy and the first three coherent actions, and say what each diagnosis would rule out."
Why it works: moving from analysis to a diagnosis that excludes options is where many strategy projects stall.
For a smaller company facing a bigger rival, see Competing Against a Much Bigger Rival Without Copying Them.
Where to go next
Richard Rumelt and Michael Porter both sit in the Business Strategist category. For the originals, read Good Strategy/Bad Strategy by Rumelt, Competitive Strategy by Porter, and his 1996 article What Is Strategy? To work through a hard choice once the strategic frame is set, Decision Brief is a $79 tool built for it.
Frequently asked questions
Are Rumelt and Porter in disagreement?
Less than the contrast suggests. Rumelt's Good Strategy/Bad Strategy criticizes strategy that is really a list of goals or slogans, and offers a kernel of diagnosis, guiding policy, and coherent action. Porter's frameworks analyze industry structure and positioning. They answer different questions, so they can sit in the same project. Reading both gives a broader view than either alone, and neither requires you to discard the other.
Which one is better for a startup?
The documented work does not rank them for startups. Porter's five forces help judge whether an industry is attractive and where pressure comes from. Rumelt's kernel helps a small team decide what the real obstacle is and commit to a coherent response. Founders often need the second to act and the first to check the terrain. If you have a clear industry with several rivals, start with Porter's analysis; if you have a plan that feels like a list, start with Rumelt's test.
What are the five forces?
In Porter's framework, industry profitability is shaped by rivalry among existing competitors, the threat of new entrants, the threat of substitutes, the bargaining power of buyers, and the bargaining power of suppliers. It first appeared in his 1979 Harvard Business Review article and in Competitive Strategy (1980). Each of the five forces can be rated for strength in your industry, which turns the framework into a short, comparable picture.
What does Rumelt mean by bad strategy?
He describes bad strategy as having recurring features: fluff, failure to face the challenge, mistaking goals for strategy, and bad strategic objectives. A plan that states ambitions without naming the obstacle is, in his account, a wish rather than a strategy. The test is whether the plan explains how it deals with a specific difficulty. He argues that a good strategy names the obstacle first, because without a diagnosis the rest of the plan has nothing to respond to.
Does Porter say strategy is about trade-offs?
Yes. His 1996 Harvard Business Review article What Is Strategy? argues that strategy means choosing a distinctive position and making trade-offs, which includes deciding what not to do. Operational effectiveness, doing the same things better, is in his account necessary but not a strategy. Fit means the activities reinforce one another, so the combination is harder to copy than any single activity on its own.
Can AI apply either framework?
It can structure a five forces analysis, draft candidate diagnoses, and challenge your assumptions. It cannot supply market facts you have not given it, or tell you which choice your organization can carry out. Treat its output as a draft to test. The more context you supply, including customer evidence and cost data, the more useful the structure it returns will be.
Written by Gareth Hoyle. Last updated 8 October 2026. Part of the authority.md guides library.
More guides.
Daron Acemoglu vs Ha-Joon Chang: Do Good Institutions Cause Growth, or Follow It?
Comparing Daron Acemoglu's institutions-first account of national prosperity in Why Nations Fail with Ha-Joon Chang's historical critique of the institutions literature: two views of development, with the main point of disagreement. General education.
Bill Ackman vs Carl Icahn: Two Styles of Activist Investing. Not Investment Advice
Comparing Bill Ackman's public, thesis-driven activism with Carl Icahn's decades of corporate pressure campaigns: how each approaches companies, boards, and the public. Not investment advice.
Adam Smith vs Ha-Joon Chang: The Founder of Market Economics and One of Its Historical Critics
Comparing Adam Smith's Wealth of Nations and Theory of Moral Sentiments with Ha-Joon Chang's history-based critique in Kicking Away the Ladder: what Smith actually argued, what Chang adds, and where they differ. General education.