4 Concept Generation and Selection
4.1 Diverge before converging
Generate multiple plausible concepts before committing to a design. Sketches, morphological charts, analogies, and simple physical experiments can reveal alternatives that would otherwise be overlooked.
4.2 Compare concepts consistently
A weighted decision matrix can make assumptions visible. First agree on criteria and weights, then score alternatives using the same scale and evidence base. Document the rationale—not only the final score.
| Criterion | Weight | Concept A | Concept B |
|---|---|---|---|
| Performance | 0.40 | 4 | 3 |
| Cost | 0.25 | 2 | 5 |
| Maintainability | 0.20 | 5 | 3 |
| Schedule risk | 0.15 | 4 | 4 |
| Weighted total | 1.00 | 3.70 | 3.65 |
On this illustrative 1-to-5 scoring scale, A scores 3.70 and B scores 3.65. This small gap is not a definitive winner; sensitivity analysis and prototypes should help decide.
Check: Safety-critical violations should not be traded away for a high weighted score.
Living chapter. This is an initial working treatment. Derivations, examples, and references will be expanded in future editions.