Six Sigma Fundamentals: A Complete Introduction to the System, Methods, and Tools

Traditionally, in the quality field we talk about a process model which is the input, process and output. In the six sigma methodology we talk about SIPOC. SIPOC is a variation of the process model—supplier, inputs, process, output and customer. It is through this model and process mapping that we identify the hidden factory and throughput yield. Throughput yield is the probability that all defect opportunities produced at a particular step in the process will conform to their respective performance standards. Roled throughput yield is the probability of being able to pass a unit of product or service through the entire process defect-free. These definitions of course, have to be understood in light of a) the normalized yield which can be thought of as the average throughput yield result one would expect at any given step of the process b) first time yield, which measures how well companies process units and c) final yield which reports on the proportion of product or service units that pass inspection. In other words, it tells us what we did. The reader may want to see item 75 in the CD for an example.