A/B tests are straightforward: try two scenarios, determine
the better of the two content variations.
Multivariate testing can theoretically test an infinite
number, though you need to keep in mind the need to maintain a statistically
significant number of results to determine a performance difference between
scenarios. It's best carried out via a
dynamically generated website: visitors
are served proportionate but random variations of content to test a
hypothesis.
Smashing Magazine artfully explains: "There are two principal
approaches used to achieve multivariate testing on websites. One being
Page Tagging; a process where the website creator
inserts Javascript into the site to inject content variants and
monitor visitor response. The second principal approach used does not require
page tagging. By establishing a DNS-proxy or hosting within a website's
own datacenter, it is possible to intercept and process all web traffic to
and from the site undergoing testing, insert variants and monitor visitor
response. In this case, all logic sits server rather than browser-side and
after initial DNS changes are made, no further technical involvement is
required from the website point of view."
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