Thursday, August 09, 2012
We've gotten several questions recently about whether website testing—such as A/B or multivariate testing—affects a site's performance in search results. We're glad you're asking, because we're glad you're testing! A/B and multivariate testing are great ways of making sure that what you're offering really appeals to your users.
Before we dig into the implications for search, a brief primer:
Website testing is when you try out different versions of your website (or a part of your website), and collect data about how users react to each version. You use software to track which version causes users to do-what-you-want-them-to-do most often: which one results in the most purchases, or the most email signups, or whatever you're testing for. After the test is finished you can update your website to use the "winner" of the test—the most effective content.
A/B testing is when you run a test by creating multiple versions of a page, each with its own URL. When users try to access the original URL, you redirect some of them to each of the variation URLs and then compare users' behaviour to see which page is most effective.
Multivariate testing is when you use software to change differents parts of your website on the fly. You can test changes to multiple parts of a page—say, the heading, a photo, and the 'Add to Cart' button—and the software will show variations of each of these sections to users in different combinations and then statistically analyze which variations are the most effective. Only one URL is involved; the variations are inserted dynamically on the page.
So how does this affect what Googlebot sees on your site? Will serving different content variants change how your site ranks? Below are some guidelines for running an effective test with minimal impact on your site's search performance.
- No cloaking. Cloaking—showing one set of content to humans, and a different set to Googlebot—is against our Webmaster Guidelines, whether you're running a test or not. Make sure that you're not deciding whether to serve the test, or which content variant to serve, based on user-agent. An example of this would be always serving the original content when you see the user-agent "Googlebot." Remember that infringing our Guidelines can get your site demoted or removed from Google search results—probably not the desired outcome of your test.
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Use
rel="canonical". If you're running an A/B test with multiple URLs, you can use therel="canonical"link attribute on all of your alternate URLs to indicate that the original URL is the preferred version. We recommend usingrel="canonical"rather than anoindexmetatag because it mo