--The problem when solved will be simple. The obvious is nearly always simple--so simple that sometimes a whole generation of men and women have looked at it without even seeing it.
--Does it check with human nature? If you feel comfortable in explaining your idea or plan to your mother, wife, relative, neighbors, your barber and anyone else you know, it's obvious. If you don't feel comfortable, it probably is not obvious.
--Does it explode in people's minds? If, when you have presented your plan, project or program, do people say, "Now why didn't we think of that before?" You can feel encouraged. Obvious ideas are very apt to produce this "explosive" mental reaction.
--Is the time ripe? Many ideas and plans are obvious in themselves, but just as obviously "out of time." Checking time lines is often just as important as checking the idea or plan itself.
--Put it on paper. Write out your idea, plan or project in words of one or two syllables, as though you were explaining it to a child. If you can't do this in two or three short paragraphs and the explanation becomes long, involved or ingenious--then very likely it is not obvious.