Research
Harvard Business School confirms ISO 9001 US certified companies out-perform similar non-certified ones
Research carried out by Harvard Business school (Levine and Tofel, 2010) among 1000 organisations, 500 with and 500 without Quality Management Systems implemented and certified, found that ISO 9001 certified organisations had a 9% higher turnover (and higher profit), higher salary levels, and in combination with ISO 14001, produced less waste and fewer incidents.
A full copy of the report is available here.