Is Once Really Enough? Making Generalizations about Advertising's Convex Sales Response Function

Jennifer Taylor, Rachel Kennedy, and Byron Sharp
Ehrenberg-Bass Institute for Marketing Science University of South

Does an advertiser get a better return by reaching two customers once, or one customer twice?

It is an extremely important issue for media planners. Single-source analysis has delivered an empirical generalization (EG): the immediate advertising sales-response function is convex, which means it is better to reach more consumers once. This empirical law appears to generalize for television advertising for established consumer goods brands in mature markets. It is such an important discovery, however, that it deserves further investigation.

In this article, we present new findings from single-source analysis in four consumer goods categories. They support the generalization by showing a dominance of convex-response functions. The convex functions are not universal, however, and we have yet to identify the boundary conditions associated with deviations from the law. Much research needs to be done before this important law can be further refined.