How do you choose criteria for a Pugh matrix?

The right criteria for a Pugh matrix are those that reflect the genuine requirements your concept must satisfy, drawn from customer needs, technical specifications, regulatory standards, and project constraints. Criteria should be independent of one another, measurable or at least assessable, and relevant to the decision being made. The sections below address the most common questions that arise when building a criteria set for concept selection.

What makes a good criterion for a Pugh matrix?

A good Pugh matrix criterion is specific, relevant to the decision at hand, and assessable by the evaluation team. It should describe a dimension of performance or value that genuinely differentiates the concepts being compared, not something all candidates will score identically on. Criteria that are too broad collapse multiple concerns into one score, while criteria that are too narrow add noise without improving the decision.

Specificity matters because vague criteria like “quality” or “performance” mean different things to different evaluators. Replacing “performance” with “pressure ratio at design speed” or “thermal efficiency under peak load” forces the team to agree on what they are actually measuring. This precision reduces subjective disagreement during scoring and makes the matrix easier to defend to stakeholders.

A criterion should also be independent of others in the matrix. If two criteria are essentially measuring the same thing, one of them is redundant and will artificially inflate the weight of that concern. Reviewing criteria for overlap before finalising the matrix saves time and produces a cleaner result.

Where do Pugh matrix criteria typically come from?

Pugh matrix criteria typically come from four sources: customer or stakeholder requirements, technical specifications, regulatory and safety standards, and project constraints such as cost and schedule. Starting from these sources ensures the criteria set reflects real-world demands rather than the preferences of whoever is running the evaluation.

Customer requirements are often captured through voice-of-customer exercises, requirements documents, or contract specifications. In aerospace and gas turbine development, these requirements are frequently detailed and quantified, covering aerodynamic performance, structural integrity, thermal behaviour, and acoustic output. Translating these into discrete, evaluable criteria is the first step in building a useful matrix.

Technical standards and certification requirements add another layer. For aerospace component development, criteria may need to reflect compliance with airworthiness regulations, material standards, or test validation requirements. These are non-negotiable and should appear explicitly in the matrix rather than being assumed as background conditions.

Project constraints, including budget, lead time, manufacturability, and availability of test infrastructure, are also legitimate criteria. Concepts that perform well technically but are undeliverable within project boundaries are not viable options, so these constraints belong in the evaluation.

How many criteria should a Pugh matrix have?

A Pugh matrix typically works best with between six and fifteen criteria. Fewer than six often means important dimensions of the decision have been collapsed or ignored. More than fifteen introduces cognitive overload during scoring and can dilute the signal from the criteria that genuinely matter.

The right number depends on the complexity of the design problem. A straightforward component selection might need only eight criteria. A full system concept evaluation in gas turbine development, where aerodynamic, thermal, structural, acoustic, and operational factors all apply, may justify closer to fifteen. What matters is that each criterion earns its place by capturing a distinct, relevant aspect of the decision.

If you find yourself with more than fifteen criteria, group related ones and decide which best represents the cluster, or consider whether some criteria are better handled in a separate, more detailed analysis downstream rather than in the initial concept selection matrix.

Should all Pugh matrix criteria carry equal weight?

Not necessarily. In a standard Pugh matrix, all criteria carry equal weight, which is appropriate for early-stage concept screening where the goal is to identify clearly superior or inferior options quickly. When the decision is more refined and some requirements are demonstrably more important than others, applying weighted criteria produces a more accurate result.

Weighting is useful when regulatory requirements or safety-critical performance thresholds must dominate the outcome. In those cases, a concept that scores poorly on a safety criterion should not be rescued by strong scores on cost or ease of manufacture. Assigning higher weights to non-negotiable requirements prevents that from happening.

The decision to weight criteria should be made before scoring begins, not after, to avoid adjusting weights to justify a preferred outcome. The weighting rationale should be documented and agreed upon by the evaluation team, with input from engineering, project management, and the customer where appropriate.

What criteria are most commonly used in aerospace component evaluation?

In aerospace component evaluation, the most commonly used Pugh matrix criteria cover aerodynamic performance, structural integrity, thermal behaviour, weight, manufacturability, cost, schedule risk, and compliance with certification requirements. The specific criteria vary by component type, but these categories appear consistently across compressor, turbine, and combustor development programmes.

For fan and compressor concepts, aerodynamic efficiency, pressure ratio, stall margin, and acoustic output are frequent evaluation dimensions. Noise performance has become increasingly significant as engine certification standards tighten, and experimental validation of acoustic behaviour, such as testing under controlled free-field conditions, is often required to confirm concept predictions before committing to a design direction.

For turbine components, thermal resistance, cooling effectiveness, and material behaviour at operating temperature are central criteria. Structural fatigue life and repairability are also relevant, particularly where components are subject to inspection and maintenance cycles over the engine’s service life.

Cost and schedule criteria apply across all component types. These include not only unit production cost but also the cost and complexity of the test programme needed to validate the concept, which can vary significantly between design approaches. Organisations working across gas turbine development and defence applications often find that test programme demands are a meaningful differentiator between otherwise similar concepts.

How do you validate that your criteria set is complete?

You can validate a Pugh matrix criteria set by checking it against four questions: does it cover all stakeholder requirements, does it reflect all applicable constraints, does it include any dimension on which the concepts actually differ, and would a poor score on any criterion be acceptable to the decision-makers? If the answer to the last question is yes for any criterion, that criterion may not belong in the matrix.

A practical validation technique is to run a brief review with people who were not involved in building the criteria set. Ask them whether any important concern is missing and whether any criterion seems redundant or unclear. Fresh eyes catch gaps that the original team has normalised.

Traceability is another useful check. Each criterion should map back to at least one source: a requirement document, a standard, a contract clause, or a documented project constraint. Criteria that cannot be traced to an external source are worth questioning, as they may reflect internal assumptions rather than real requirements.

It is also worth reviewing the criteria after scoring is complete but before a final decision is made. If the matrix produces a result that feels wrong to experienced engineers, that is often a signal that a relevant criterion is missing or that one criterion is doing the work of several. Revisiting the criteria set at that point, before acting on the result, is a legitimate part of the process.

How AneCom supports concept evaluation in aero-engine development

AneCom AeroTest provides engineering and testing services that directly support the experimental validation stage of concept selection for aero-engine and gas turbine components. When concept evaluation criteria include acoustic performance, aerodynamic efficiency, or thermal behaviour, test data is often needed to score concepts with confidence rather than relying on analysis alone. AneCom’s capabilities are specifically relevant here:

Multistage compressor and fan testing in a dedicated Compressor Test Center, providing performance data that maps directly to aerodynamic and pressure ratio criteria
Acoustic testing in Europe’s largest anechoic chamber, which suppresses wall reflections below 1% across 200 Hz to 40 kHz, producing free-field noise data applicable to certification-relevant criteria
Combustor and turbine test services through cooperation partners, covering thermal and structural performance criteria
Non-destructive testing and instrumentation services that support repairability and inspection-related criteria in component evaluation
Engineering services available from a single source, including design, analysis, and test execution at customer sites worldwide

If your concept selection process requires validated test data to score candidates against performance or acoustic criteria, contact AneCom to discuss how testing can be integrated into your evaluation programme.