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Concept Refinement

Refining design concepts in light of the results of concept evaluation helps you find the best possible concept early in a design process.

You've performed a concept evaluation exercise, but you still have more than one design concept that seems viable.

Now you want to tweak the remaining concepts to see if you can come up with even better ones. This is concept refinement.

How can we refine concepts?

There are 4 ways of doing this.

Add entirely new concepts

It may be that, in the course of carrying out the concept evaluation, you or your team mates discovered some new concepts. This is the time to add them into the mix. Alternatively, you may return to develop one or two more design concepts as you did earlier in the process.

Documentation: Remember to note how it was that the new concept was conceived of; you'll need to explain this in your design report.

Fix the worst aspects of the best concepts

You may have a concept that fared well in the decision matrix in all but one or two significant criteria and, as a result, got a relatively weak overall score. If you can improve its performance in just those one or two areas, the concept might become a leading contender. So consider such concepts carefully, and look to see if anything can be done about those one or two significant aspects in which the concept did poorly.

Documentation: Remember to note how exactly you changed each concept; you'll need to explain this in your design report.

Consider the best aspects of the worst concepts

Even the worst concept may have done well with respect to one or two criteria. Is there some way to “borrow” those good aspects of the bad concepts and embed them into another, more successful concepts? If you can embed a good aspect from a poor concept into a good concept, it might make the good one even better.

Documentation: Remember to note which concepts were “borrowed” from, what you did with them, and why; you'll need to explain this in your design report.

Blend two of the best concepts together

Take, say, the second and third best designs and see if you can combine them together into some new, combined concept. It might result in a new concept that is the best of all.

Documentation: Remember to note which concepts were combined, how you did that, which features you kept, and which you discarded; you'll need to explain this in your design report.

Adding refined concepts to the decision matrix

Each new or modified concept must get its own column in the decision matrix.

For example, say you are designing a stapler and there was one concept – concept B – that evaluated very well, except in the area of cost. Say further that you have found a way of addressing that problem. You do not just change concept B. Instead, you leave concept B and introduce a new concept – say, B' or B2 – which embodies the modification. Now you have to evaluate B' as if it were an entirely new concept.

If you have blended two concepts – say, concepts B and D – then the blended concept could be called BD to indicate how it was derived, and would get its own column in the decision matrix.

You can name the concepts whatever you like, so long as you are consistent and sensible.

This is very important: each concept must be evaluated in its entirety. You cannot just cut and paste values from the original columns into the new columns. This is because changing one feature of a concept may have implications for other features. If you get this wrong, and choose the wrong concept because you evaluated them incorrectly, then you've ruined your chances of coming up with a good design at the end.

Remember, never add more new or modified concepts than you removed in a previous iteration, or you'll never converge to a “best” design concept. So, for instance, if you started your decision matrix with 10 concepts and eliminated 7 of them via concept evaluation. In this refinement stage, you would only add 2-5 new concepts.


The deliverables of the concept refinement activity includes (a) the concepts that survived the last concept evaluation stage and (b) a few more concepts that you developed during refinement (of course, with explanations of how you generated the new concepts).

You now have to add the new concepts to the decision matrix and conduct another concept evaluation activity.

You keep looping like this, in principle, until you have found a single concept that is a clear winner.

However, in classes, where there is limited time, you only need to do the concept evaluation activity twice (with one pass through concept refinement between them). Thereafter, you can just pick the “best” concept from the DM.

design/concept_refinement.txt · Last modified: 2020.03.12 13:30 (external edit)