How does Six Sigma apply in all sectors, companies or industries?

Six Sigma can be applied in all industries/companies as work always takes place in processes and the following hold true for every company (in any industry).

• Everything that anyone does is a part of a process.
• A process is efficient or inefficient depending on the output to input ratio. (this ratio could be productivity measure, cost measure, time measure or any other useful metric)
• Very few processes are defect free and most have unacceptable level of defects or delays (as per industry standards, company's own philosophy towards defects or based on customer expectations). Here, for many processes there is an internal customer (instead of or in addition to an external customer).
• Meeting customer (internal, external or both) expectations with reasonable cost is a key success criterion.
• Variation in process inputs or improper controls result in reduced efficiency or dissatisfied customers, which increases costs and breeds further inefficiency.
• Six Sigma requires that you define success criteria for key processes, eliminate defects (or reduce their severity or occurrences), and rigorously measure outcomes for exceeding industry standards or creating new benchmarks, thereby leading to competitive advantage in terms of cost or value for customers.