Six Sigma
- Six Sigma is a statistical approach which aims to drive up profits by putting special effort into ensuring goods or services conform to specification
- It’s applicable to repetitive, relatively simple processes
- Six Sigma is about eliminating unpleasant surprises and broken promises via:
- Reducing any variation in the outputs from processes – defects or delivery times say – by ensuring virtually all meet certain minimum standards
- Reducing waste and inefficiency
- Redesigning a company’s products and internal processes so that customers get what they want, when they want and when they were promised
- It’s not about averages but removing variation from customers’ interfaces with you
- Getting things right 95% of the time is often just not good enough:
- Deliveries to your home must be made when you’re in and waiting, not an hour or two later when you’ve had to go back to work
- Personal computers must work when millions switch them on, every time, not 99 times out of 100
- Airlines must not lose luggage, hospitals must not make mistakes – for you
- Six Sigma is Statistical Process Control with extremely strict control limits:
- SPC usually requires some 99.97% of the output from any process to fall within three standard deviations of the average – in other words 0.03% (3 defective items in every 10,000) may fall outside this range
- Six Sigma aims for no more than 3.4 defects per million – covered by a range of 6 standard deviations from the average
- The latter maximum failure rate is vital for a company like Intel – imagine if you bought a computer which often didn’t work because of a dodgy chip they’d made
