6σ is not a tool and more than just the figure 6 and the greek symbol; σ. It is an achievement, a goal....
It appears to be more robust than thought with different range of tools for solving different problems. I can say that 6σ is the mind behind the various tools developed to achieve business excellence in the aspect of quality improvements. Its ambition is to keep improving the system until there is nothing to improve anymore. It solve problems strategically and systematically,with the consideration of the impact on the organisation and customers' need.
Having gone through most of the training module on the PMI online learning, I have understood that 6σ cannot be achieved without the people. There would only be more chaos in the system if the team members do not understand their roles and or unwilling to perform their responsiblities within the team because every team members' constructive input is important and can lead to a huge success in the over all project.
This could be said that generally for any oragnisation to achieve business excellence, process improvement, learning, a good measurements of result, they need genuine committments from the staff. But I can't argue any less by the way because really the people are the ones who make up the organisations at the end of the day. Yes there are machines, but who operate them? This is obviously where Deming can help!