Transfer Function

Transfer Function Y=f(X) - A transfer function describes the relationship between lower level requirements and higher level requirements. If it describes the relationship between the nominal values, then it is called a y-hat model. If it describes the relationship between the variations, then it is called an s-hat model.

Y is the dependent output variable of a process. It is used to monitor a process to see if it is out of control, or if symptoms are developing within a process. It is a function of the Xs that contribute to the process. Once quantified through Design of Experiment, a transfer function Y=f(X) can be developed to define the relationship of elements and help control a process.

Y is the output measure, such as process cycle time or customer satisfaction. f is the transfer function, which explains the transformation of the inputs into the output. X is any process input process step that is involved in producing the output.

For example, if you call your major department store to ask a question, the ability to have your question answered (Y) is a function (f) of the wait time, the number of people answering the phones, the time it takes to talk with the representative, the representative's knowledge, etc. All of these X's can be defined, measured and improved.

[Category=Data Quality ]

Source: iSixSigma, 28 February 2011 10:45:51, https:web.archive.org/web/20111109014246/http:www.isixsigma.com/index.php?option=com_glossary