Porter's Diamond (Michael Porter, 1990) explains why some countries are a strong base for particular industries. It has four determinants: factor conditions, demand conditions, related and supporting industries, and firm strategy, structure and rivalry, with government and chance also influencing them.
The determinants explained
| Determinant | What it covers | Example |
|---|---|---|
| Factor conditions | Inputs: skilled labour, infrastructure, capital, knowledge. Advanced, specialised factors matter more than basic ones | Engineering skills and universities supporting a car industry |
| Demand conditions | Demanding home customers who push firms to innovate and improve quality | Sophisticated local buyers of fashion or technology |
| Related and supporting industries | Strong local suppliers and connected industries, often in clusters | A cluster of suppliers around a technology hub |
| Firm strategy, structure and rivalry | How firms are managed and how fiercely they compete at home; strong domestic rivalry drives improvement | Intense competition among domestic firms in one sector |
| Government (outside the diamond) | Policy, regulation, subsidies, education and infrastructure investment influence all four | Tax incentives for research and development |
| Chance (outside the diamond) | Events outside firms' control: inventions, wars, shifts in demand | A breakthrough technology |
How to use Porter's Diamond in the SBL exam
- Use it when the case is about international expansion, choosing where to locate production or a new office, or explaining a rival's international success.
- Assess each determinant for the country in question using the case information.
- Combine it with PESTEL for country risk and with Five Forces for the local industry.
- Conclude: is this country a strong base for the organisation's activity, and what are the risks?
Worked example
A software company choosing between two countries for a new development centre would compare: factor conditions (supply of developers, salary costs), demand (sophisticated local clients to test products), related industries (an existing tech cluster, investors, universities) and rivalry (strong local competitors that raise standards but compete for talent), plus government incentives. The country with the stronger cluster may win even with higher costs.
Porter's Diamond vs Five Forces
Five Forces asks "is this industry attractive?" The Diamond asks "is this country a good base for this industry?" In SBL internationalisation questions, the two work best together.
Advantages and limitations
Advantages
- Explains location-based advantage clearly
- Useful for international strategy and site selection
- Highlights the value of clusters
Limitations
- Built mainly on developed economies
- Less relevant where supply chains are global and digital
- Government and chance are hard to assess
- Explains national advantage rather than a single firm's strategy
Clusters: why the determinants reinforce each other
Porter's key insight is that the four determinants form a system. Strong home demand attracts suppliers; good suppliers improve firms; intense rivalry drives innovation, which raises the skill level of the workforce, which attracts more firms. The result is a cluster, a geographic concentration of connected firms and institutions. Examples often cited include technology in Silicon Valley, financial services in London and fashion in northern Italy. In an SBL case, the presence or absence of a cluster is often the strongest argument for or against a location.
Using the Diamond for each type of decision
| Decision | Determinants to focus on |
|---|---|
| Where to sell (export market) | Demand conditions, plus a country PESTEL |
| Where to manufacture or source | Factor conditions, related and supporting industries |
| Where to put research or innovation | Factor conditions (skills, universities), rivalry, clusters |
| Explaining a foreign competitor's strength | All four determinants in its home country |
Criticisms and extensions
Critics argue the model underplays multinational firms that draw advantages from many countries at once. Rugman and D'Cruz proposed a "double diamond" that combines the home country with a larger neighbouring economy, which suits smaller open economies. In a world of global supply chains and remote work, a firm's advantage can come from networks rather than one national base, so use the Diamond as one input, not the final answer.
FAQs
What is Porter's Diamond?
A model from Michael Porter's The Competitive Advantage of Nations (1990) explaining why some countries are home to internationally successful industries, based on four determinants plus government and chance.
What are the four determinants of Porter's Diamond?
Factor conditions; demand conditions; related and supporting industries; and firm strategy, structure and rivalry.
What is the difference between Porter's Diamond and Porter's Five Forces?
Five Forces assesses the attractiveness of an industry. The Diamond explains why a particular country is a strong base for that industry.
How is Porter's Diamond used in ACCA SBL?
To evaluate whether to expand into, source from or locate operations in a particular country, alongside PESTEL for that country.