Overcoming doubt in the NPD process

When inventors and start-ups come to us for our product development services they have already heard from the outside sources in doubting their product ideas. Engage doubt and use it as positive feedback, so don't be stubborn.  We all know that when you’re pushing a new idea there are things to do better.

This is especially true when you’re in the early stages and developing your “story” as to why the idea should get turned into a product.  What are some things you might be over-confident about that the doubters might actually be saying?