Six Sigma is a method that provides organizations tools to improve the capability of their business processes. The main philosophical perspective behind Six Sigma is that all work and processes can be defined, measured, analyzed, improved, and controlled. This increase in performance and decrease in process variation helps lead to defect reduction and improvement in profits, employee morale, and quality of products or services.
Lean manufacturing is a production process aiming to maximising value while simultaneously minimising waste within manufacturing or working processes. Lean defines “waste” as anything that doesn’t add value and anything that the customers are not willing to pay for. The benefits of lean manufacturing include reduced lead times and operating costs and improved product quality.
Whilst Six Sigma focuses on reducing process variation and enhancing process control, Lean drives out waste (non-value added processes and procedures) and promotes work standardisation and flow.
Which one is better? As the two strategies or philosophies aren’t in competition and solve different problems, you don’t need to compare and choose one of them. You can integrate both and implement the so called Lean Six Sigma.
Lean thinking aims to remove wastes from work processes. The original seven wastes were defined by Taiichi Ohno, the Chief Engineer at Toyota. These 7 type of wastes (Muda) are:
There are 5 types of waste, not so famous as the above, but equally important and implicitly tackled by Scrum, an Agile framework based on empirical process that aim to maximise the value produced by people working in team and teams of teams.
The 2 types of waste deriving from unevenness (Mura) are:
The 3 types of waste deriving from overburden (Muri) are: