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Concept Evaluation - Coggle Diagram
Concept Evaluation
13. Decision Matrix – Key Features
Designer selects evaluation criteria
Criteria weighted for importance (W.F.)
Weighting factors sum to 1.0
→ Reflects relative importance of requirements
14. Decision Matrix – Scoring
Each concept rated 1–10 per criterion (R.F.)
Rated weighting factor:
R.W.F. = R.F. × W.F.
All R.W.F. values summed
→ Highest total score = selected concept
15. Advantages of Decision Matrix
More quantitative
Allows fine comparison
Suitable when concepts are more developed
→ Better for later design stages
1. Purpose of Concept Evaluation
Compare alternative design concepts
Identify the concept with the highest potential
Avoid developing weak or unviable designs
→ Ensures resources are focused on the best concept
2. Importance of Concept Evaluation
Developing multiple concepts is costly
Time and resources are limited
Only the most promising concept should proceed
→ Early selection reduces cost and waste
3. Difficulties of Concept Evaluation
Limited data available
Concepts are abstract and low‑detail
Performance cannot yet be measured accurately
→ Decisions must be made under uncertainty
4. Alternative Concepts
Generated using tools like:
Functional analysis
Morphological charts
Result in multiple feasible combinations
→ Creates the need for structured comparison
5. Need for Structured Selection Methods
Informal judgement is biased
Structured tools improve objectivity
Enable transparent decision‑making
→ Justifies concept choice logically
9. Pugh Matrix – Scoring
Four outputs:
Total +
Total –
Overall total
Weighted total
Equal scores require further evaluation
→ Helps narrow down the best concept
8. Pugh Matrix – Key Features
Each concept scored as:
better than datum
0 same as datum
– worse than datum
Weighting factors applied to criteria
→ Qualitative but structured evaluation
7. Pugh Evaluation Matrix (Overview)
Relative comparison method
Uses a reference (datum) concept
Compares concepts against criteria
→ Fast, intuitive comparison tool
6. Concept Selection Methods
Pugh Evaluation Matrix
Decision Matrix
→ Two systematic approaches for concept evaluation
20. Importance of Concept Selection
Guides detailed design direction
Reduces redesign risk
Improves chance of successful product
→ Critical step in the design process
19. Overall Concept Selection Process
Identify customer requirements
Convert to engineering criteria
Generate concepts
Evaluate using structured method
Select best concept
→ Logical, defendable decision path
18. Role of Criteria
Must be relevant to the design task
Often derived from:
Customer needs
PDS
Poor criteria = poor decisions
→ Criteria quality determines selection quality
17. Pugh vs Decision Matrix (Key Differences)
Pugh:
Relative comparison
Qualitative (+/0/–)
Early‑stage use
Decision Matrix:
Absolute scoring
Quantitative (1–10)
Later‑stage use
→ Choice depends on design maturity
16. Limitations of Decision Matrix
Requires more data and judgement
Can give false accuracy if data is weak
More time‑consuming
→ Still dependent on designer judgement
12. Decision Matrix (Overview)
Absolute scoring method
Concepts judged directly against criteria
More quantitative than Pugh Matrix
→ Detailed and analytical evaluation
10. Advantages of the Pugh Matrix
Simple and quick to apply
Encourages comparison instead of absolute judgement
Reduces early bias
→ Useful in early design stages
11. Limitations of the Pugh Matrix
Relatively subjective
Depends heavily on chosen datum
Limited numerical precision
→ Best for initial concept filtering