I introduced and supported a “Business Process Breakthrough” program that uses some principles of Six Sigma and that relies on simple measurements like cycle time. The method uses a number of creative techniques for unearthing root causes and for finding cures.
I developed this method while running an engineering company and broadened its scope while consulting to a machinery manufacturer and a processed food manufacturer. The results were: dramatic improvements in throughputs with minor investments. The ROI was very big.
I later used this method for customer acquisition process and distribution process leading to good results.
In my opinion:
TQM is too abstract and indirect for most managers and process players.
TOC is really a problem solving framework and a not problem defining technique.
Both above techniques fail to provide pro-active look-ahead controls in the hands of managers.
Lean methods specify a philosophy and asks managers to manage accordingly. They have limited diagnostic and control abilities.
Six Sigma: is the most powerful but extremely demanding in terms implementation and therefore rarely gets applied to wider business processes. It is usually restricted to manufacturing sub-processes.
The biggest gains can be obtained in wider business processes for which the method I developed has been very effective in terms time to see results (3 to 6 months typically) and easier acceptability by managers. The method provides both diagnostic and controlling tools to managers.