Impact of A/B testing on Search Engine Optimization (SEO)
Update: there is even an official confirmation from Google’s Matt Cutts that split testing does not impact search rankings.
A lot of our potential customers are concerned whether A/B or multivariate testing will have an effect on their search engine rankings. They (obviously) aren’t looking to improve their rankings by using A/B testing, rather their concerns relate to the myth that testing may negatively impact search engine optimization efforts.
Broadly, there mainly two major concerns:
- Duplicate Content: the act of copying content from elsewhere and hosting it on your site. Search engines penalize for such stealing of content because you cannot expect to rank on keywords for the content that isn’t yours. Again, many A/B and multivariate testing software (including VWO) have an option where you can redirect site traffic to different variations of a page which raises this concern.
Why A/B testing is not content cloaking
Cloaking content was all rage back in the early days of search engines (think 1990s). In those days, SEO was all about keyword stuffing. So, smart SEO geeks used to display a page full of keywords when a search engine bot visited to crawl / index the page. While if a user visited the same page, they displayed the default (normal) version. This strategy of keyword stuffing used to work like wonders so naturally search engines started devising clever ways to detect and penalize such cloaking and it may appear that pages where A/B testing is on will also get penalized because it is kind of cloaking.
Good news is that thanks to Google’s PageRank algorithm, keyword stuffing no longer works. So, there is little incentive for search engines to penalize content cloaking. Moreover, unlike yesteryears’ static HTML sites, today’s search engines have come to expect highly dynamic AJAX driven sites. So, they no longer consider swapping content dynamically as cloaking. If you use a multivariate testing software to swap different parts of your page, it is not cloaking! Also, all the major search engines (Google, Yahoo, Bing, etc.) are well versed with concept of A/B split testing and they do many such tests on their own sites every single day. You wouldn’t expect search engines to penalize others for doing the same activity that they themselves do regularly, would you?
Split URL testing (redirecting traffic to multiple versions) and the issue of content duplication
As I mentioned above, this is another issue that worries many prospective customers. While one approach for split testing is to dynamically swap page elements (such as headlines, images, text, etc.), another approach is to host different variations of page on your website. So, if you want to split test product.html, you will create variation pages and host them as product1.html, product2.html, etc. A split testing software will redirect all traffic coming to product.html to the variation pages. Since product1.html and product2.html will have similar content as product.html, it worries some people that search engines will consider them duplicate content and penalize rankings.
An important point to note here is that search engines only penalize if you steal or host content from a different domain; here all variations pages host on your own site and you OWN that content and are free to do with it whatever you want to. Many dynamic websites (shopping carts, directories, etc.) today host the same content in different formats. Search engines don’t penalize them because that unique content is only found on their domain and no where else. Same is the case with your split testing URLs. You don’t get negatively impacted by it because you haven’t stolen that content — it is all yours!
A more important point is answer to this question: how will search engines come to know that there are different variations of your main page? Your variation pages can only be reached if there is a link pointing to it. Since you don’t link to your variation pages from anywhere from the site or else-where, search engines won’t know that those pages even exist. For the truly paranoid, you can instruct search engines not to index you variations pages. You can do it either using no-index meta attribute or by using robots.txt
Lesson: A/B split testing has absolutely NO negative impact on your SEO efforts!
Rest assured, you can use Visual Website Optimizer without worrying about its impact on search engine rankings. If you have a specific SEO and A/B testing related question, let me know in comments below.
UPDATE: Things have changed since this article was written. Please see http://googlewebmastercentral.blogspot.in/2012/08/website-testing-google-search.html for Google’s guidelines on A/B testing.