As marketers, we use the word attribution in many ways. Attribution quite simply is applying appropriate, or earned credit to the marketing touch-point that led a conversion. Typically, attribution is attempted through one, or more methods, such as first-touch, last-touch, MTA and so on.
Incrementality measurement solves for the attribution problem statement, however the methodology goes about the task in a very different way from MTA. To measure incrementality, audiences are randomly segmented into test and control cohorts. The difference in conversion rates between the two cohorts effectively gives us incrementality and an accurate read on the marginal incremental contribution of that media channel.
Incrementality in marketing is especially needed for channels where ad impressions are difficult to map and measure such as walled garden social channels including Facebook, Snap and Pinterest, or even TV and direct mail. For most channels or platforms, MTA cannot measure views or impressions, so you’re essentially just measuring clicks. Incrementality measurement accounts for the impressions and clicks within each of the platforms under test and therefore gives marketers a more accurate view of the true contribution of their media across their entire portfolio.