How do I test the effectiveness of different segments?

Testing segment effectiveness requires controlled comparison:

Comparative analysis: Send the same email to different segments and compare results. This reveals which segments are most responsive.

Segment vs control: Compare each segment's performance to a random sample of the full list. This shows whether the segment definition captures something meaningful.

Cross-segment testing: Send segment-specific content to both the target segment and other segments. If "loyal customer" content works equally well for new customers, your segment may not be distinctive.

Metrics to compare:

Engagement rates (opens, clicks). Conversion rates. Revenue per recipient. Response to specific offers or content.

Effective segments behave meaningfully differently from each other and from the general population. If they do not, the segmentation is not adding value.