What is multivariate testing (MVT) in email?

Multivariate testing (MVT) tests multiple variables simultaneously, measuring how different combinations interact to affect performance. Unlike A/B testing which isolates single changes, MVT examines how elements work together.

For example, you might test two subject lines, two hero images, and two CTAs simultaneously. MVT measures all eight possible combinations to find which overall configuration performs best.

MVT reveals interaction effects that A/B testing misses. A casual subject line might work better with a friendly image but worse with a formal one. MVT captures these relationships.

The tradeoff is complexity and sample size. Each additional variable multiplies the combinations tested, requiring substantially larger audiences to achieve statistical significance.

MVT answers "what works best together" rather than "which single element is better." It is powerful but demanding, best suited for high-volume senders with mature testing programs.