How do I measure segment performance against a control group?

Measuring segment performance against a control requires careful experimental design:

Create a true control: Randomly select a sample from your full list before segmentation. This represents what would happen without targeting.

Send identical content to both segment and control to isolate the targeting effect from the content effect.

Calculate comparative metrics:

Lift = (Segment result - Control result) / Control result × 100. For example, 4% conversion in segment versus 2.5% in control = 60% lift.

Statistical validation: Ensure differences are statistically significant given sample sizes.

ROI calculation: Compare lift against the cost of segmentation (analysis time, content creation, complexity).

Control groups reveal what would have happened otherwise. Without them, you cannot know if segmentation actually helped.