A bathtub model is a rules-based model that allocates a set amount on the first and last touchpoints of a conversion path, and taking the remainder and allocating an equal amount to the middle touchpoints. For instance, let’s say your conversion path consists of Email >> Video >> Display >> Paid Search >> Retargeting. If we configure the bathtub model to allocate 70% to the end points (meaning that Email gets 35% and Retargeting gets 35%) then the remainder gets distributed evenly to the intervening touchpoints (meaning that Video gets 10%, Display gets 10% and Paid Search gets 10%)
Note that events may happen beyond a particular lookback window — and these will not receive any credit. For example, if the marketer has a 30-day lookback window in the above example, and a Paid Social event actually happened 31 days before the conversion event — then that Paid Social event does not receive any of the credit because it occurred before the 30-day lookback window.
