Multivariate Testing
Definition
A testing method that compares multiple variables on a webpage to determine the best-performing combination.
Example Use Case
A travel booking site tests different headlines, images, and CTA buttons to maximize conversions.
Multivariate testing changes several elements at once — headline, image, button text, layout — and measures the combinations, so you learn not only which individual elements perform best but how they interact. It answers a question A/B testing cannot: whether the winning headline still wins alongside a different image.
The cost is traffic. Testing every combination multiplies the variants needed, and each one requires enough conversions to be meaningful. A page with modest traffic is usually better served by sequential A/B tests, even though they take longer to reach the same conclusion.
It is most valuable on high-traffic pages where a single lift compounds, and where the elements being tested genuinely interact. Where they plainly do not, the extra combinations buy nothing. As with any test, decide the primary metric and the stopping rule before starting.
