This is the most basic form of conversion testing. You compare 1, 2 or 3 alternatives to the original version of a landing page, home page or even elements of the home page. Each design is tested over a period of time and the conversion data is collected. Based on the conversion metrics set, the variation that gives the best conversion is the one that is implemented.

A-B split tests are normally conducted with two versions of a design, but in some case you will have 3 or 4 designs in which case it will be referred to as A-B-C-D split test. “A” is always the original version and is sometimes referred to as “baseline” or “control.”

A-B split tests can be conducted on individual elements of a page like calls to action, headlines, copy, offer, or element colors. They can also be used to compare completely unrelated versions of your whole page. There are pros and cons to both approaches. If you only test individual elements within their current context, you will not be able to capture the advantages of a comprehensive "clean sheet" page redesign. But you will be able to tell the exact impact of changing the element in question. If you choose to test completely redesigned pages, you will not know which elements contributed to the improved performance. You will also incur higher design costs without knowing if you will have a favorable outcome.