The document discusses concepts for evaluating and selecting between alternative solutions to meet a need or design brief. It outlines a process that involves generating multiple conceptual solutions, evaluating them using methods like decision matrices and concept scoring matrices, then selecting the most promising concept(s) to further develop. Key steps include establishing evaluation criteria, using techniques like Pugh matrices to rate concepts relative to a baseline, applying weights to criteria, calculating weighted scores to rank concepts, and iteratively combining, improving or retaining concepts before final selection. The goal is to objectively compare conceptual solutions at an early stage to inform decisions about which to advance.

1. CONCEPT
EVALUATION/SELECTION
CUPE 125
By Bamhare J
Engineering Design Principles

2. Journey So Far
■ Need/Mission statement/Design Brief
■ Stakeholder Identification – Active, Passive
■ Requirements capture, grouping & prioritization –
Stakeholder needs
■ Functional Decomposition
■ Concept Generation – Number of alternate solution concepts
attempting to satisfy the need

3. Next Step
■ Decide which conceptual solutions are good
potential candidates for further investigation/
product development
– ALL ?
– Some ?
– One ?
■ Concept Evaluation
– Evaluation criteria
– Compare generated concepts: strengths & weaknesses wrt
criteria
■ Concept Selection
– Decision making: Eliminate, Retain, Combine, Modify
– One Shot / Stages/ Iterative (?)
– Final Selection
Resources,Time, Risk, Policy,
Culture

4. Difficulties/Issues
■ Limited knowledge/data
■ Conceptual solutions - Rough/abstract ideas
■ Concensus among team members
■ Other ??

5. Some methods
■ External Decision – company chairman?, customer
■ Product Champion – personal preference
■ Voting – team concensus (subjective)
■ Intuition – feel good factor
■ Prototype & test – Expensive & time consuming
■ Decision Matrices – relatively more objective

6. Process overview
■ Initial filtering – qualitative, absolute comparison
■ Quantitative screening based on decision matrix –
Pugh Matrix
– Prepare matrix
– Rate concepts
– Rank concepts
– Combine/improve/retain promising concepts
– Select one or more concepts
■ Concept Scoring – similar steps, weighted scores,
more refinement and advancement over Pugh
matrix

7. Evaluation Criteria
■ Extracted from stakeholder requirements
■ Identify a few key requirements through
prioritization
– Primary, secondary, tertiary
■ Level of abstraction/refinement of requirements
must be consistent with concept abstraction/
refinement
There is No Sense in Being Exact About
Something if You Don’t Even Know What
You are Talking About
(John von Neuman, 1950)

8. Initial Filtering (absolute)
(In case of large number of concepts)
■ “Gut feel” feasibility judgment
– Comparison made with prior experience (“design knowledge”)
■ Concept will not work
– Too radical
– Not original
■ Conditional feasibility – something else required
■ Feasible -Worth considering
■ Go - No go screening
■ Customer requirements
■ Technology readiness/maturity/availability

9. Pugh Matrix
■ Select one concept as a reference or datum
– Familiar, straightforward concept
– Existing similar benchmark product in market
– Existing product in case of re-design/ modification problem
– Arbitrarily picked from the generated concepts
■ Pair-wise relative rating of each concept vs datum for each
criteria
– Better than datum: +
– Same as datum: 0
– Worse than datum: -
■ Count number of pluses and minuses for each concept.
Overall rating is difference between no. of pluses and no. of
minuses.
■ Rank the concepts based on overall rating

10. Pugh Matrix Structure
Concepts
Selection Criteria A B C D E F G
Handling ease 0 0 - 0 0 - -
Ease of use 0 - - 0 0 + 0
Readibility of settings 0 0 + 0 + 0 +
Metering accuracy 0 0 0 0 - 0 0
Durability 0 0 0 0 0 + 0
Ease of Manufacture + - - 0 0 - 0
Portability + + 0 0 + 0 0
Sum of +’s 2 1 1 0 2 2 1
Sum of –’s 0 2 3 0 1 2 1
Net rating 2 -1 -2 0 1 2 1
Rank 1 6 7 3 2 3 3
Continue? Yes No No Comb Yes Comb Rev

11. Concept Scoring Matrix
■ Select one concept as a reference or datum
– Best in Pugh Matrix
■ Select weights for each criteria
– Importance rating of each criterion: scale of 1 to 5 or %age with total = 100%
etc.
■ Relative rating of each concept vs datum for each criteria. Datum maybe
different for each criterion
– Much better than datum: 5
– Better than datum: 4
– Same as datum: 3
– Worse than datum: 2
– Much worse than datum: 1
– Finer scales (1 to 9) etc. may also be used.
■ Weighted score for each concept – criterion pair
■ Rank the concepts based on total score (sum of weighted scores)
■ Combine/ Improve/ Retain concepts
■ Select one or more concepts

12. Concept Scoring Matrix Structure
Concepts
Selection Criteria A DF E G+ Weights
R Scor R Scor R Scor R Scor
Handling ease 3 0.15 3 0.15 4 0.2 4 0.2 5%
Ease of use 3 0.45 4 0.6 4 0.6 3 0.45 15%
Readibility of settings 2 0.2 3 0.3 5 0.5 5 0.5 10%
Metering accuracy 3 0.75 3 0.75 2 0.5 3 0.75 25%
Durability 2 0.3 5 0.75 4 0.6 3 0.45 15%
Ease of Manufacture 3 0.6 3 0.6 2 0.4 2 0.4 20%
Portability 3 0.3 3 0.3 3 0.3 3 0.3 10%
Total Score 2.75 3.45 3.10 3.05
Rank 4 1 2 3
Continue? No Develop No No

13. Selection process
Generation Screening Scoring Selected