I just read Po Bronson's article The Creativity Crisis in Newsweek. I'm referring here mostly to practical creativity [inventions, innovations, outside-the-box efficiency gains, etc.] not artistic creativity [better paintings, more beautiful statues or books, etc.].

Where should one go to find formal, scientific tests of the thinking strategies such as those from:

• Edward de Bono's Lateral Thinking
• Edward de Bono's Six Thinking Hats
• Jump Start Your Brain by Doug Hall
• The other creativity stuff out there, e.g. Wikipedia on creativity
• Breakthrough Thinking

Ideally, the evidence comes from a well designed randomized controlled trial. Most creativity "tips" and strategies I've found are based on anecdotes or correlational studies. Or, even worse, they come from bald-faced statements like "All children are unique like snowflakes! Set them free so they can sparkle creatively in their own special way!" or "Chant ommm ommm ommm in a Himalayan cave until you are enlightened."

I'm looking for something a little more rigorous.

Thinkertoys by Michael Michalko is pretty good. From his bio:
As an officer in the U.S. Army, he organized a team of NATO intelligence specialists and international academics to research, collect and categorize all known inventive-thinking methods.

Cool. I will definitely check that out.