I read once about a man who tripled his conversion rate by changing a single letter in his headline. While that kind of improvement is not common (not by a long stretch), you can quite probably double your conversion rate after testing 10 or 20 items on your page. With that said, there are many things to consider when getting started with split testing.
Let me give you an overview, so you can understand the choices you have before you. I’ll walk you through the main distinctions that rule the field.
The first main division is between simple split testing (single variable) and multivariate testing.
Single variable split testing is very simple. You just try stuff and measure the results. And all you need is a tool that rotates and keeps score.
Paul Hancox has a simple split testing tool. And Google has one that’s free, though it takes a bit to set up all your accounts to use Google’s tool. And the reporting is not real-time.
Single variable testing can be slow. How would you like to test 10 times as much with the same amount of traffic? Well, you can. You use a method called multi-variable, or multivariate testing. This allows you to test several elemens on your page simultaneously.
Among multiple variable software solutions, there are hosted plans and self-install plans. If you want to install software on your server (which can be faster and cheaper) you will have more control over your data. And you can usually find someone to install it for you (often the vendor provides this service for a nominal fee). If you want to go with a hosted plan expect to pay more.
Hosted solutions include Google’s Website Optimizer, and Vertster. Installed solutions include the Split Test Accelerator and Kaizen Track.
The next distinction probably causes the most confusion among people looking into split testing for the first time. It’s also more important than the last distinction, becuase it determines how fast and accurate your tests can be. The three kinds of testers are 1) random independent rotators, 2) Taguchi testers, and 3) full-factorial testers. Taguchi ranks first for speed and second for accuracy. Basically Taguchi testing involves using a marvel of mathematics known as “orthogonal arrays”. These have special properties that allow you to test every combination in a space while running only a small fraction of the actual combinations. You have to be a little bit careful about interaction effects with Taguchi testing. The Split Test Accelerator and Kaizentrack are Taguchi testing tools.
Full factorial tools allow you to cycle through all the combinations for your factors. So if you have 3 headlines, 3 offers, 3 P.S. statements, and 3 images you’re testing, you will cycle through 81 pages. One advantage of full factorial testing is that you don’t have to worry as much about interaction effects. Good and bad interactions should show up in the data. However, if you want to receive this advantage, you have to run many times the traffic through your test as you would with a Taguchi test. You also can’t run as many combinations. Google’s website optimizer is a full factorial tool.
The Random independent rotators are a third option. These treat factors independently. So you can just plug in a new factor with as many options as you want at any time, and ignore the fact that other factors are being tested at the same time. This is the most flexible form of testing, but it is also plagued with the most interaction effects.
There are other distinctions and features worth noting. And each solution has a different mix of pros and cons. But this should get your oriented a bit before you make your decision.
Dominic DeLong has used multivariate testing software for years to improve landing pages.
