Google Website Optimizer is a fantastic tool. For those of you who are not familiar with GWO, it is a free tool provided by Google to use to test elements of your website in order to increase traffic and conversions, or even to A/B test completely different layouts. Many people say that A/B or multivariate testing WordPress sites is a pain.
I found some resources that might be helpful to people who want to A/B or multivariate test their site.
Steps to A/B or Multivariate Testing Your WP Site
Step 1: Decide what you want to test
This, I think, is the hardest part of multivariate testing. What do you want to test? You need to decide what the goal of your website is. Is it to increase leads? Up your conversion rate? Get RSS subscribers? Figure this out, then move to Step 2.
Step 2: Build your site so that you have a final conversion point
Google Website Optimizer requires that you have a final place for your visitor to land in order to consider an action a “conversion.” If you want to increase signups for your service, you should have a final page where the person arrives after completing the action. For example, if your goal is to have someone complete a form to send you a lead, send them to a “Thank You” page after they submit the form.
Step 3: Create a copy of your page that you want to test
Continuing on our example of a contact form to gather leads, now you should create an alternate version of your Contact page. In WordPress, what I would recommend is creating a new page, with its own unique URL, that contains the changes you want to test. Save this page, but don’t link to it from anywhere. Also, make the URL something that you would not be ashamed using as your Contact page URL, or be prepared to implement the same changes on your existing page and redirect the better performing page to that URL.
Step 4: Set up your GWO account
Before you can start testing, you have to set up your GWO account. Go here to sign up using your Google account. You are allowed up to 10 tests at a time.
Follow the steps to setting up your experiment. They’re pretty straight-forward.
Step 5: Install the Google Website Optimizer for WordPress plugin
Now you are ready to install the Google Website Optimizer for WordPress plugin (which I use on this site also). What this plugin does is install a box on each post and page in the admin section of your site. It will look like this:

Step 6: Enter the scripts provided to you by GWO into the correct box
The Google Website Optimizer website will provide you with the scripts for your Control (the original page, most likely) page, the Tracking Script for both the Control AND Variation pages, and the script for your conversion page. Follow the instructions for each section in the plugin.
Step 7: Monitor through GWO
GWO offers tracking for you. Once you validate that the scripts are correctly involved, sit back and allow data to collect. You need to get at least 100 conversions to have valid numbers off of which to base decisions. The more traffic you can get, the quicker and better your data will be.
Conclusion
I’ve only really talked here about A/B testing, which is good for testing while new layouts, and forms. You can also multivariate test, which means that you can test individual elements on your page, such as the color of buttons. This is more involved, and I will not explain it in this post. Unfortunately I have not yet found any good resources for multivariate testing WordPress. I plan to write about it in the future.
If you know of any good resources for WordPress multivariate testing, please leave them in the Comments. I’d also love your feedback.