The Shainin system, including Shainin DOE, is a set of methods that are good complementary tools to formal DOE and other problem-solving methods.
An excellent reference is World Class Quality (Bhote).
The Shainin website: http://www.shainin.com
Wikipedia information on the Shainin system: http://en.wikipedia.org/wiki/Shainin
Articles that address Shainin methods may be found at the links below.
Related problem solving methods include:
Kepner-Tregoe or Kepner-Fourier
"The New Rationale Manager" by Charles H. Kepner and Benjamin B. Tregoe
Wikipedia entry for Kepner-Tregoe (http://en.wikipedia.org/wiki/Kepner-Tregoe)
Official Kepner-Tregoe website (http://kepner-tregoe.com)
Official Kepner-Fourie website (http://www.kepner-fourie.com)
"Guide to Quality Control" by Kaoru Ishikawa
Cause and Effect Diagrams
Check Sheets
Pareto Diagrams
Wikipedia entry (http://en.wikipedia.org/wiki/Kaoru_Ishikawa)