When we do not see the dip, we can infer that this segment does not exist. Since it is rare to find the dip, I have come to believe this segment is quite small. No, that is not the case. But we can identify conditions where we might see it. Pantry stock is not related to consumption.
Some people report the existance of post-promotion dips in scanner data.
This may be the case, but I think it is a relatively rare phenomenon because the conditions listed above do not occur often. The noisy nature of real data make it difficult to determine the existance of a dip. This chart plots weekly retail sales data for a brand of coffee creamer in a single market. Detecting post-promotion dips is difficult because it is hard to find a promotion that has steady state conditions before and after the event. In these instances, one must resort to econometric models to take out trends and the effects of known events, as well as model the dip.