Intervention Analysis of a Field Experiment to Assess the Buildup Effect of Advertising

The authors study the buildup effect of increased advertising using time series intervention analysis. The data are from an ADTEL field experiment with test and control panels connected to a split-cable TV system. Use of the control series in the analysis depends on the nature of the relevant external factors. If these factors are purely unmeasured, the control series is included as a covariate, resulting in a single-input transfer function-intervention model. If there are also measured external factors, a multiple-input model results. A careful analysis of the increased advertising shows that the buildup effect is immediate with a duration of the order of the purchase cycle.