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Home→The Westburn Dictionary of Marketing→E→envelope curve

envelope curve

Definition:
Broadly speaking, a curve that summarizes a number of subsidiary curves is known as an envelope curve. As an analytical tool it has found wide application in the study of the path of technological progress. In this context an envelope curve is an S-curve that envelops a series of subsidiary S-curves which plot the historical development of a performance parameter, functional capability or some other attribute of an advancing technology. An envelope curve will describe the pattern of development of a specific technology: the series of S-curves contained within the envelope will represent the emergence of substitute developments and new applications of the technology. As an example, Figure 11 shows the envelope curve which follows the historical development of illumination technology. It plots the progressive improvements made to the parameter lighting efficiency (lumens/watt) as a result of the development of two specific illumination devices - each the product of successive technical advances. The envelope curve is the line that is drawn tangential to the subsidiary S-curves.

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© Westburn Publishers Ltd 2002, The Westburn Dictionary of Marketing edited by Michael J Baker, ISBN 978-0-946433-01-8. www.themarketingdictionary.com. Entry: [Douglas Brownlie and Michael Baker], [1998].