Incrementality refers to a measurement of advertising effectiveness that can be measured by attribution at multiple dimensions of granularity: channel, campaign, keyword, placement, etc… It indicates the amount of lift to a particular metric (i.e. incremental sales, incremental conversions, etc…) that is brought about by the marketing investment — comparing, for example those who were exposed to or clicked on a particular channel, campaign, keyword, placement, etc… versus one who had not had that touchpoint.
Incrementality can often be measured effectively by more advanced attribution algorithms, such as ones that leverage advanced statistical or machine learning techniques that calculates the likelihood of an increase on the target metric based on the presence or absence of a particular touchpoint in both customer journeys that end in conversion and ones that do not.
