A/B testing (also known as bucket testing or split-run testing) is a user experience research methodology.[1] A/B tests consist of a randomized experiment with two variants, A and B.[2][3] It includes application of statistical hypothesis testing or "two-sample hypothesis testing" as used in the field of statistics. A/B testing is a way to compare two versions of a single variable, typically by testing a subject's response to variant A against variant B, and determining which of the two variants is more effective.[4]