January 21st, 2011 by Dr. Thomas M. Fehlmann
During the last years a tendency has been observed to position QFD more towards understanding customer’s needs than doing complex matrix mathemagics with insecure data and producing fuzzy evaluation profiles. It is more important saving (customer’s) time than understanding relationships between process controls and process response.
Customer’s needs can be analyzed by means of Thomas Saaty’s Analytic Hierarchical Process (AHP), prioritized with ratio scales, and assessed for consistency. This seems much quicker and more reliable than assessing the Voice of the Engineers, and then trying to understand how it transforms into something that meets Voice of the Customer’s requirements.
However, this opinion stands in contrast to the Six Sigma approach, used to define, measure, analyze, improve, and control (DMAIC) relationships between process controls and process responses. Such relationship mapping is called Transfer Function. For instance, a transfer function describes how to transform controls used by engineers into response expected by customers. If there are more than one response characteristics, and more than one control impacts the response, the QFD matrix is the natural choice for representing the transfer function.