How would you define incrementality?

Incrementality measures the direct causal impact of an ad campaign on user behavior, such as sales or conversions. It determines how many additional actions occurred because of the ad, beyond what would have happened naturally without it. This is crucial for understanding the true value and return on investment (ROI) of advertising efforts. The other options are incorrect because: Testing variations of ad creative is A/B testing, not incrementality. Near real-time attribution for short-term decisions describes last-click or multi-touch attribution models, which don't isolate causal impact. Top-level modeling including media and external factors is typically Marketing Mix Modeling (MMM), which provides a broader view but isn't focused on the direct causal impact of a specific campaign in the same way incrementality is.