What is uplift modeling evaluation and how is Qini coefficient used?

Uplift evaluation measures treatment effect at individual level; Qini coefficient measures ranking quality of uplift models.

Uplift modeling estimates incremental impact of an action (treatment vs control). Evaluation focuses on how well a model ranks individuals by treatment effect. The Qini coefficient measures the area between uplift curve and random baseline. Unlike classification metrics, uplift evaluation is causal and requires counterfactual reasoning or randomized data.