What are the differences, similarity between Six Sigma & Total Quality Management and which is better ?

Good question.

Six Sigma = Total Quality Management (TQM) minus weaknesses of Total Quality Management (TQM)

Historically TQM initiatives at most companies have been found to be weak for the following reasons.

• No structured training was designed. Introduction of Six Sigma initiated structured training.
• Projects were not supported well by senior management. Whenever operations urgency emerged, TQM assignments were stalled or postponed. Six Sigma has project charters that needed approval.
• TQM was taken as a Quality management initiative although it did contain the word "TOTAL". Six Sigma created a mechanism of engaging people.
• There was no mechanism of using world best techniques in a sequence. It was unclear how output of one techniques can become the input for another. Six Sigma DMAIC and DMADV provided the answers.
• There was no organizational structure for TQM implementation. Six Sigma provided a structure with Champions, Sponsors, MBBs, BBs, GBs, etc.
• Statistical usage was limited in most TQM initiatives and they mostly hovered around 7 QC tools or Quality Circles. Six Sigma brought in more rigor with statistical techniques, starting from graphical tools and hypothesis testing to the most advanced simulation, forecasting and experimental design methods.
• Linkage with startegic goals was missing in TQM. In making use of TQM philosophy, any project was ok as long as it improved Quality. In Six Sigma, projects have different levels and significance. Several TQM projects would not get approved as Six Sigma projects as they do not have a strong business case. (linkage with strategic objectives)
• TQM used more of Lean concepts and philosophy and were culture change drivers with improvements. Six Sigma is used by selected (and specially trained) people who can (or need to) tackle the more complex chronic problems.

Hope this helps.

Best Regards,


VK