Gatlin Education Six Sigma Green Belt - OVERVIEW Why Do Six Sigma - Page 9

Service Example Let us look at a simple example from a service process that many of us are familiar with. The Internal Revenue Service has many processes, one of which is the tax advice service they provide each spring to millions of their customers. Like any process, we can usually define both opportunities and potential errors in a number of ways. For this case, we will assume an opportunity is a particular customer contact via phone, email or fax (even though several requests may be made on a particular contact), and an error occurs anytime incorrect advice is given on one of these contact occasions. If the error rate calculated using statistical techniques is found to be 40%, we recognize that is equivalent to saying there is 0.40 Defects per Opportunity. To convert the DPO to DPMO (defects per Million Opportunities), we multiply by 1 million, resulting in 400,000 DPMO. Referring to Appendix 1 in the Six Sigma Deployment text, we see this is equivalent to a Sigma Level of 1.75. Simple enough?