On page 16 of the November 2010 issue of Harvard Business Review, under the heading "Your Voices," it says:
"A poor idea worked on by the right people is salvageable. A good idea worked on by the wrong people is not."
That's a very interesting observation. Certainly a good design team can take a mediocre idea or plan and make it better as they go. In fact, one of the marks of a good design team is that they can, and generally do, refine the plan as they work on it, thereby making the final product so much more than was originally envisioned during the early planning stages of the project.
Many people in the A/E/C industry use the words "effective" and "efficient" interchangeably. In truth, the two words are not interchangeable. To be effective means to do the right thing; to be efficient means to do the thing right. In other words, the former is about doing the correct thing, while the latter is about doing a thing in the correct manner.
When the poor idea mentioned above is sufficiently improved as the project progresses, the idea will likely become effective. But if the good idea is worked on by the wrong people, the odds are it will never be efficient.
Both -- effectiveness and efficiency -- are necessary, but neither is sufficient (my old economics professor would be stunned that I remember this concept!).
Therefore, before you worry about doing the thing right, always make sure you are doing the right thing!