02 · Porter’s five forces
WHAT TO CHECK
A narrow boundary can hide substitutes, while a broad boundary can mix unrelated economics. The definition must match the customers, suppliers, entrants and alternatives being compared.
A force should be supported by observable conditions such as concentration, switching costs, access barriers or fixed costs. A label such as high power is a conclusion that must remain traceable to those conditions.
A useful conclusion identifies defensible positions, dependencies to reduce and assumptions to monitor. It does not compress the analysis into a single attractiveness score.
METHOD QUALITY PROTOCOL
Use the question “Where can value be captured or eroded in a sector’s structure?” as a contract: name the owner, deadline, scope and alternatives before collecting more material. The analysis connects every force to observable drivers, changes over time and the strategic positions that remain available. Record what is deliberately outside scope, who can challenge the framing and what consequence follows from postponement. This prevents an attractive framework, actor list or market story from silently replacing the decision that the analysis is meant to support.
METHOD QUALITY PROTOCOL
For every material statement, retain the original source, publication date, observation period, method, unit and relevant population. Distinguish observed facts, calculated estimates, interview judgements and assumptions. Connect the register to the promised output: A documented reading of the pressures that distribute value among sector participants. Missing or contradictory evidence remains visible with a responsible owner and a collection action; it is never converted into certainty merely to complete the page.
METHOD QUALITY PROTOCOL
Define the rules before applying the analysis: inclusion criteria, identifiers, comparison set, calculation or coding convention, treatment of missing values and version date. Reproduce the same convention across every option or actor. Use the page checks as acceptance tests, beginning with “Stabilise the sector boundary and the need served by substitutes.” A conclusion is usable only when another practitioner can reconstruct how the inputs became the displayed result and identify where judgement entered.
METHOD QUALITY PROTOCOL
Challenge the preferred interpretation with at least one plausible alternative, contradictory observation and sensitivity test. Separate association from prediction and never infer intent, power or causality from a position, score or visual proximity alone. The standing limit remains: The model describes sector structure. It does not guarantee a company's performance or automatically recommend market entry. State which uncertainty is most likely to reverse the conclusion and what additional observation would discriminate between the competing explanations.
METHOD QUALITY PROTOCOL
Turn the analysis into a dated decision record rather than a static page. Preserve the selected option, rejected alternatives, objections, accepted risks and first reversible action. Name the signal, numerical or qualitative threshold, review owner and review date that will confirm, adapt, pause or reopen the decision. Link every later update to its author and reason so that the history remains understandable when evidence or market conditions change.
METHOD QUALITY PROTOCOL
Define Porter’s five forces in operational terms before using it. State the decision unit, market boundary, time horizon and comparison set. The method must answer “Where can value be captured or eroded in a sector’s structure?” without quietly expanding its scope or replacing the decision with a descriptive classification.
METHOD QUALITY PROTOCOL
Ask an independent reviewer to identify what is included, excluded and held constant. The page passes only when two practitioners would analyse the same unit and period. Ambiguity is recorded as an assumption and assigned an owner before calculation or categorisation begins.
METHOD QUALITY PROTOCOL
Translate the method into a concrete marketing case with a named customer, offer, market or portfolio question. Preserve at least two genuine alternatives plus the status quo. The expected deliverable is A documented reading of the pressures that distribute value among sector participants. and must make trade-offs visible rather than presenting one preferred option as inevitable.
METHOD QUALITY PROTOCOL
Verify that the question can be answered by a choice, commitment or learning action. A broad request to understand the market is not sufficient. Record who decides, by when, which resources are constrained and what would happen if no option were selected.
METHOD QUALITY PROTOCOL
Explain which part of the decision Porter’s five forces illuminates and which parts require another lens. Compare it with a plausible alternative method. Selection should follow the uncertainty to reduce, not habit, visual appeal or the availability of a familiar two-by-two matrix.
METHOD QUALITY PROTOCOL
Describe the mechanism in plain language before introducing labels or scores: what changes, for whom, through which link and over what period. Mark the link as observed, estimated or assumed. A diagram may aid understanding, but proximity or quadrant membership never establishes causality.
METHOD QUALITY PROTOCOL
List every required field with definition, unit, geography, population, observation period, source and refresh date. Distinguish missing data from zero and not applicable. Use stable identifiers so updates reconcile the same market, segment, competitor or business unit across versions.
METHOD QUALITY PROTOCOL
Check primary sources first and document transformations applied to secondary data. Compare like with like: currency, nominal or real values, calendar period, perimeter and denominator must match. Any conversion or proxy retains its formula, reason, confidence and effect on the decision.
METHOD QUALITY PROTOCOL
Write the formula, coding rule or classification convention used by Porter’s five forces. Define every symbol, scale anchor, weight and sign. Explain whether a higher value is favourable, adverse or merely descriptive, and prevent a weighted average from compensating a binding constraint.
METHOD QUALITY PROTOCOL
Recalculate totals, ratios and classifications from the displayed inputs. Check units, denominators, rounding and missing-value treatment. Preserve the unrounded value for reproduction and display the rounded value consistently. Any threshold is labelled as an agreed convention rather than a universal fact.
METHOD QUALITY PROTOCOL
Describe the sequence from collection to decision: frame, gather, qualify, calculate, challenge, compare and record. For each step, identify the responsible role, input, output and acceptance condition. Separate mechanical operations from judgements that require an accountable human decision.
METHOD QUALITY PROTOCOL
Provide a compact example whose inputs, intermediate operations and final result can be followed line by line. Use realistic but explicitly simulated values. The narrative conclusion must match the numbers, while alternative assumptions show how a different result could legitimately emerge.
METHOD QUALITY PROTOCOL
Convert each material assumption into a question, observable indicator, source, threshold and review date. Separate assumptions testable with current data from those requiring an experiment, interview or future observation. Do not mark an assumption as validated merely because stakeholders agree with it.
METHOD QUALITY PROTOCOL
For every diagnostic attached to Porter’s five forces, state what is calculated or observed, how to interpret it and what action follows when it fails. A warning without a response rule is incomplete. Record whether failure blocks the decision, changes confidence or triggers additional evidence.
METHOD QUALITY PROTOCOL
Vary the most uncertain inputs, scale anchors and weights across defensible ranges. Test alternative market boundaries and plausible missing values. Report which changes leave the recommendation stable and which reverse it; do not hide instability behind a single central estimate or colour.
METHOD QUALITY PROTOCOL
Search deliberately for observations that contradict the preferred reading. Compare at least one rival mechanism and identify the evidence that would discriminate between them. Distinguish association, prediction and causal claims, and reduce the wording whenever the available design cannot support the stronger claim.
METHOD QUALITY PROTOCOL
Interpret the result at the level supported by the evidence. Keep this boundary visible: The model describes sector structure. It does not guarantee a company's performance or automatically recommend market entry. Explain magnitude, uncertainty, business relevance and affected option separately. Avoid converting a descriptive category into a forecast or a forecast into proof of causal impact.
METHOD QUALITY PROTOCOL
Publish two explicit lists: conclusions supported by the analysis and conclusions that remain unsupported. Include tempting overclaims such as guaranteed performance, universal superiority or inferred intent. Connect every permitted conclusion to the exact calculation, observation or source that supports it.
METHOD QUALITY PROTOCOL
State the marketing action the result can inform, the first reversible step and the conditions under which the method should not be used. Preserve rejected alternatives and objections. The recommendation remains conditional on the evidence, constraints and review signals documented on the page.
METHOD QUALITY PROTOCOL
Version the dataset, dictionary, parameters, code or worksheet and expected output. Record source localisers, licences and checksums where artefacts are retained. Name the reviewer, publication status and reopening signal. A future team must reproduce the result without guessing hidden conventions.
LIMIT
