Assessing the Impact of Market Disturbances Using Intervention Analysis

A recurring problem confronting marketing operatives at all levels is assessing the impact of market disturbances. The disturbances may be caused by marketing mix manipulations of the firm itself, by its competitors or by fundamental external changes in the environment in which the firm operates. This article discusses a technique, intervention analysis, by which the impact of such disturbances can be assessed. The technique is used to examine the effects of Proctor and Gamble's promotion of the American Dental Association endorsement of Crest on the market shares of Crest and Colgate dentifrice during the years 1958–1963.