A/B and multivariate tests on the Internet allow a website to test two or more versions of the same page and measure desired outcomes. A/B split testing allows one to:
randomly divide your visitors into two groups and show each group a different version of a page to determine which version leads to higher conversion, average order value, application completion, or other target. These visitors are then tracked and a report is generated that describes the impact of the A or B page version on this outcome. (Roche, 2004)
Multivariate testing, on the other hand, is:
a process by which more than one component of a website may be tested in a live environment. It can be thought of in simple terms as numerous split tests or A/B tests performed on one page at the same time. (Search Engine Marketing, 2009)
One example of this practice would be a site testing the placement of a search box on the page in order to see if it gets used more frequently depending on whether it is on the top right or left of a page. This type of testing came about long before the Internet and was used for many different purposes; however, the Internet allows for easy use and quick testing of many different design elements at the same time. Results can also be quickly linked to sales related figures such as percentage of shopping carts abandoned or average order size.