NON LINEAR ADVERTISING RESPONSE:
Practitioners in media modeling world often use complicated non-linear functional forms to estimate media response curves. For instance, a common approach is to assume that the media response curve is S shaped, i.e. has an initial convex and subsequently a concave section. This S shape is a result of two different factors: (1) threshold effects of advertising: the phenomenon that marketing efforts are not effective until they reach a certain minimum level and (2) diminishing returns to scale: the fact that too much advertising leads to a reduction in its effectiveness at the margin. This has led to the use of a non-linear S shaped media response curve by practitioners. Apart from these effects, there are a large variety of different factors to take into account including various types of media, advertising lags and multiple brands / markets / stores, all of which increase the complexity in the relationship between advertising and sales often leading to the use of complicated functional forms to get a good fit.
Guest Contributor Pat Bhattacharya, Managing Principal, Thinkalytics