01 · Competitive rivalry
How intensely do existing firms compete?
Look at concentration, differentiation, switching costs and the structure of competition between firms.
Read rivalry notes →Strategy field notes
Porter's Five Forces, made usable.
Porter's Five Forces is a way to examine the competitive pressure around an industry. This guide explains each force, what to look for, and how to turn observations into a better strategic question.
Five lenses
Read the pressure around a market.
Each note isolates one force. Use the set together; one attractive signal rarely settles the whole analysis.
02 · New entrants
What makes entry difficult or easy?
Examine capital, regulation, distribution, scale economies and the responses an incumbent can make.
Read entrant notes →
03 · Supplier power
Who controls important inputs?
Map concentration, uniqueness, switching costs and the possibility of taking an activity in-house.
Read supplier notes →
04 · Buyer power
How much leverage do customers have?
Consider buyer concentration, price sensitivity, information and the cost of changing provider.
Read buyer notes →
05 · Substitutes
What solves the same problem another way?
Substitutes are not only direct rivals. They can be different products, processes or choices serving the same need.
Read substitute notes →A practical starting point
Describe the mechanism before scoring it.
Begin with observable structure: who supplies, who buys, what can change, and where value leaks away. A written explanation is usually more useful than a decorative high-medium-low chart.