Glossary
Multivariate testing (MVT)
An experiment that varies several page or product elements at once, to measure each element's individual effect and how elements interact.
Multivariate testing changes multiple elements of a page or experience at the same time, a headline, an image, and a button color, for example, and tests combinations of them against each other, rather than testing one change in isolation the way a standard A/B test does. A full factorial design with three elements at two versions each produces eight combinations to test simultaneously.
Because it tests combinations rather than a single change, MVT can also measure interaction effects, cases where two elements together perform better or worse than the sum of their individual effects, something a series of separate A/B tests run one at a time cannot detect on its own. The cost is traffic: each additional element or variant multiplies the number of combinations, which multiplies the sample size needed to reach a usable minimum detectable effect for every combination, or even for each element's main effect.
MVT is worthwhile on high-traffic pages where enough visitors exist to power every combination and where element interactions are plausible and worth knowing about, a homepage or a checkout flow, for instance. On lower-traffic pages, or when the goal is simply to know whether a single change helps, a sequence of standard A/B tests usually reaches a reliable answer faster than a full multivariate design.
Last reviewed September 22, 2026