The Pugh Matrix

The development of new products, systems, and processes requires organizations to make informed choices between multiple solution concepts. During almost every design project, several concepts emerge that appear capable of meeting the specified requirements, yet differ significantly in aspects such as technical feasibility, cost, performance, reliability, manufacturability and usability. Consequently, the design phase often represents the greatest challenge within the development process. This challenge does not arise from a lack of available concepts, but rather from determining which concept provides the strongest foundation for further development (Pugh, 1991; Ulrich & Eppinger, 2016).

Within engineering design, this stage is referred to as concept selection. The objective of concept selection is not merely to identify a single preferred alternative, but to systematically compare multiple design concepts against a predefined set of requirements and evaluation criteria. A structured concept selection process reduces the likelihood that decisions are driven solely by intuition, personal preferences, or organizational influence, thereby contributing to a more objective and well-founded design process (Pahl et al., 2007; Ulrich & Eppinger, 2016).

One of the well-known methods for concept selection is the Pugh Matrix. Developed by Stuart Pugh as part of his Total Design philosophy, the Pugh Matrix provides design teams with a structured method for comparing alternative concepts. Rather than evaluating each alternative independently using absolute scores, the method compares every concept against a selected reference concept using predefined evaluation criteria (Pugh, 1991; Pugh, 1996).

Although the Pugh Matrix is frequently described as a decision matrix or evaluation matrix, these labels do not fully reflect Pugh’s original intention. Pugh regarded the matrix primarily as a comparison matrix—a tool designed to highlight the differences between competing concepts and to facilitate structured technical discussions within the design team. It was never intended to function as a purely numerical scoring model capable of automatically identifying the best design solution (Pugh, 1991).

A second defining characteristic of the method is that concept selection is not viewed as a one-time activity. Within the Total Design approach, the Pugh Matrix forms part of an iterative design process in which concepts are continually evaluated, refined, and compared. As a result, the method not only supports the selection of an existing concept but also encourages the creation of improved concepts that combine the strongest features of previous alternatives. Pugh referred to this iterative process as controlled convergence (Pugh, 1991; Pugh, 1996).

Although originally developed for product development and engineering design, the Pugh Matrix has evolved into a widely used technique across a broad range of design and innovation disciplines. Today, it is applied in areas such as industrial product development, systems engineering, mechanical engineering, and design management. In addition, often in adapted form, the method is frequently used in innovation projects and other decision-making processes where multiple alternatives must be evaluated systematically (Ulrich & Eppinger, 2016).

The popularity of the Pugh Matrix largely stems from its simplicity. The method does not require complex calculations or advanced statistical techniques. Instead, it encourages teams to think explicitly about the evaluation criteria, the relative strengths and weaknesses of competing concepts, and the rationale behind their decisions. In doing so, it contributes to a more transparent, structured, and reproducible decision-making process (Pugh, 1991; Ulrich & Eppinger, 2016).

The following sections provide a concise overview of the structure of the Pugh Matrix and explain how the method can be applied in practice.

The structure of the Pugh Matrix

The Pugh Matrix consists of three fundamental elements:

• The evaluation criteria;
• The alternative design concepts;
• A selected reference concept.

The evaluation criteria are typically listed in the first column of the matrix, while the alternative design concepts are displayed across the top. One of these concepts serves as the reference concept, or baseline, against which all other alternatives are compared.

For each evaluation criterion, the performance of every alternative is assessed relative to the reference concept. In the original method, Pugh used only three possible ratings:

• Better than the reference (+)
• Equal to the reference (0)
• Worse than the reference (−)

This distinguishes the Pugh Matrix from many later decision-making models that rely on extensive scoring systems or weighted numerical values. The emphasis of the Pugh Matrix is not on calculating an exact overall score, but on making the relative differences between competing concepts explicit. The outcome is therefore a structured comparison showing the criteria on which each concept performs better, equally well, or worse than the selected reference concept (Pugh, 1991).

This does not imply that additional scoring systems or weighting factors cannot be incorporated. However, such extensions are not part of Pugh’s original methodology. They may be introduced when a more quantitative comparison is considered desirable, but they should be regarded as adaptations rather than components of the original Pugh Matrix (Ulrich & Eppinger, 2016).

Applying the Pugh Matrix

The application of the Pugh Matrix consists of seven sequential steps, which are outlined below.

Step 1. Define the design concepts

The first step is to identify the alternative concepts that will be compared. These concepts are typically the outcome of the preceding concept development phase and should be sufficiently developed to allow a meaningful evaluation.

Assume an organization intends to develop a new packaging machine. During the concept development phase, three potential solutions have been identified:

• Concept A: A conventional mechanical design.
• Concept B: A modular design with interchangeable components.
• Concept C: A fully automated design incorporating robotic technology.

These three concepts constitute the alternatives that will be evaluated using the Pugh Matrix.

Step 2. Define the evaluation criteria

The next step is to establish the evaluation criteria. According to Pugh, these criteria should be be derived directly from the Product Design Specification (PDS) to ensure that the comparison remains aligned with the original design objectives (Pugh, 1991).

For a packaging machine, for example, the evaluation criteria might include:

• Investment cost;
• Production capacity;
• Maintainability;
• Energy consumption;
• Reliability;
• Safety;
• Ease of use;
• Flexibility for future expansion.

Not every project will evidently use the same evaluation criteria. The selected criteria should always reflect the specific requirements established earlier in the design process.

Step 3. Select a reference concept

A distinguishing characteristic of the Pugh Matrix is that all alternative concepts are compared against a single reference concept, often referred to as the baseline. The reference concept does not have to represent the best available design. In practice, it is commonly one of the following:

• The current product;
• The existing process or working method;
• One of the newly developed design concepts.

In the packaging machine example, the organization’s existing packaging system is selected as the reference concept.

Step 4. Compare each concept with the reference

In this step, every design concept is evaluated against the selected reference for each individual criterion. For every criterion, it is determined whether the alternative performs:

• Better than the reference (+);
• Approximately the same as the reference (0);
• Worse than the reference (−).

A simplified example is shown below.

Criterion	Reference	Concept A	Concept B	Concept C
Investment cost	Baseline	+	−	−
Reliability	Baseline	0	+	+
Maintainability	Baseline	−	+	0
Energy consumption	Baseline	+	+	−
Flexibility	Baseline	−	+	+

This comparison immediately highlights the strengths and weaknesses of the individual concepts relative to the selected reference.

Step 5. Analyse the differences

Once the matrix has been completed, the focus should not immediately shift to identifying the concept with the greatest number of positive ratings. More importantly, the results should be analysed to understand why the differences exist.

Typical questions that can guide this discussion include:

• Why does Concept B perform better in terms of maintainability?
• Why is Concept C more expensive while offering greater flexibility?
• Which evaluation criteria are truly critical for the success of this project?
• Are there criteria on which all concepts perform inadequately?

According to Pugh, this structured discussion represents the primary value of the method. Rather than producing a numerical winner, the matrix stimulates critical thinking and encourages design teams to understand the trade-offs between competing alternatives before making design decisions (Pugh, 1991).

Step 6. Develop an improved concept

The analysis does not necessarily conclude with the selection of one of the existing alternatives.

For example, the evaluation may reveal that Concept B offers excellent maintainability, while Concept C performs better in terms of reliability and automation. Rather than selecting one concept outright, the design team may decide to combine these strengths into a new and improved design concept.

This reflects the principle of controlled convergence, in which the objective is not only to evaluate existing concepts but also to create superior solutions by integrating the best characteristics of competing alternatives.

Step 7. Repeat the comparison

The newly developed concept is subsequently added to the Pugh Matrix and compared once again with the remaining alternatives. This creates an iterative design process in which concepts are continuously refined and improved over successive evaluation cycles.

Each new comparison generates additional insights that can be used to further optimise the design. According to Pugh, this continuous cycle of comparing, improving, and re-evaluating concepts represents the essence of effective concept selection (Pugh, 1991; Pugh, 1996).

REFERENCES

1. Pahl, G., Beitz, W., Feldhusen, J., & Grote, K.-H. (2007). Engineering Design: A Systematic Approach (3rd ed.). Springer.
2. Pugh, S. (1991). Total Design: Integrated Methods for Successful Product Engineering. Addison-Wesley.
3. Pugh, S. (1996). Creating Innovative Products Using Total Design: The Living Legacy of Stuart Pugh. Addison-Wesley.
4. Ulrich, K. T., & Eppinger, S. D. (2016). Product Design and Development (6th ed.). McGraw-Hill Education.