Incrementality Index
The incrementality index reflects the percentage of the customer journey that should be attributed to a certain traffic source. It represents the amount of incremental value of a traffic source in percentages.
Our definition of incremental value:
The extent to which a sale can be attributed to a
specific traffic source, expressed as a percentage.
Therefore, our incrementality index is the foundation of Odyssey. The incrementality index determines whether you are spending too much, or too little, to a specific traffic source. This is represented by the suggested media spend. You can see the effects of the incrementality index by comparing your suggested media spend to your current media spend.
How we calculate incrementality
Three KPI's
The incrementality index is being calculated based on our three main KPIs (length, density, and position). This data is collected from your Google Analytics data. We just use the available data. When data is missing, we don’t make any assumptions.
Attribution model
Then we look at the attribution model. Therefore, our standard choice is the First Click Linear Model. But you are free to choose whatever model you prefer.
Incrementality
Thereafter, it's simple. Based on the chosen attribution model, Odyssey will calculate the incrementality by a mathematical formula. And like we said, that's no secret.