Exploring the six sigma phenomenon using multiple case study evidence

Purpose This research paper aims to: explore areas of weakness in six sigma implementations that may require enhancements in the methodology; to investigate implementation differences between manufacturing and services; and to investigate critical success factors. Design/methodology/approach Exploratory empirical evidence is presented from nine case study companies in Thailand, including manufacturers, sales and service companies and a national airline. Findings Key findings include: six sigma is more appropriate for high risk, complicated, large‐scale and cross functional projects; the six sigma methodology could be enhanced to ensure that projects are aligned to company goals; the evidence questions standard text book advice that a “Black Belt” (BB) should have a full time role, as a part‐time BB role can be more realistic particularly in a small company and the training materials available need to be improved to be more appropriate for service operations. Research limitations/implications The main research limitation is in the number of companies studied and the restriction to companies located in Thailand. In addition, the research is exploratory and future research is needed to look at the issues raised in depth. Practical implications All of the findings have practical implications. For example, the conclusion on the nature of the BB role is seen as a key issue for successful use of six sigma in small businesses. Originality/value Six sigma has been widely used in industry, but there has been limited rigorous academic research. This paper seeks to identify a series of issues worthy of further attention from the academic community using a rigorous research approach.