Six Sigma and the TOC

Just ran into this excellent Six Sigma presentation.  What stikes me is how closely it is related to the theory of contraints.  The PMBok does mention Six Sigma but only in passing and what is interesting is the focus on finding the important variables just like in TOC.  Six Sigma DMAIC 

• Define
  
• Measure
  
• Analyze
  
• Improve
  
• Control
  

is linked to controling only the important variables.  

In TOC the focus is on defining the contraint 

• 0. Set the goal 
  
• 1. Identify the constraint 
  
• 2. Decide how to exploit the constraint
  
• 3. Subordinate all other processes to above decision (align all other processes to the decision made above)
  
• 4. Elevate the constraint
  
• 5. If, as a result of these steps, the constraint has moved, return to Step 1.

In a way the language is different but the key is intense focus on the most important factors. TOC is more production oriented with the assumption that the desired result is clear ie. think of the Factory in "The Goal" while Six Sigma seems to add more ambiguity in the casue effect relationship to finding the constraint.