Time decay models reward the media touchpoint closest to conversion most and the others receive less credit the earlier they are in the path. Time decay models reward path position regardless of the relative effectiveness of each of the channels in the customer journey. Just like most rules-based models, they ignore external factors.
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.
