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How WikiJob increased sales by 34% by A/B testing customer testimonials

In the past, we have featured a number of A/B testing case studies. In many of those case studies, a number of elements change which contribute to increased sales and conversions. However, this case study is special. Here a single (seemingly trivial) change was responsible for increasing sales by as much as 34%. This is unprecedented and, of course, is an amazing story which demonstrates the power of A/B testing.

That’s why I chatted with Chris Muktar of, UK’s largest graduate jobs website. Started in 2007, it now attracts over 500,000 visits a month. Started by two friends, it has grown to be a profitable company employing several staff, and proudly boasts many of the world’s largest brands as their clients.

WikiJob use Visual Website Optimizer for A/B testing and below is the interview where Chris talks about how they managed to boost bottomline sales by 34% just by testing a small element.

What conversion goals were measured in the test?

There were two conversion goals. The first was to click through to Paypal checkout. The other was to complete it and actually buy something.

On which page did you run the test?

What is the traffic source? Organic, direct, PPC, etc.?

Most of the traffic was from our main website. The traffic to our website is almost entirely organic.

Which part of page did you select for the test and what variations did you test?

We’ve tested a number of things in the past and had some great results. This time we were testing the effect of three lines of testimonials given by customers and their impact on sales. Below are screenshots.

– Original Page –

– Variation (with screenshots): 34% increase in sales –

Why did you think that the variations you created had better chances to beat the original? What were you actually testing in this test?

A previous test displayed the same testimonials further down the page and had no discernable impact on conversion. However, it’s commonly thought that social proof can help in the sales process, so we wanted to leave nothing to chance and test it.

What results did you get? Were you surprised by the results?

Testimonials increased sales by 34%. The testimonials we used are very ‘sober’ (compared with the overly enthusiastic ones you so often see in marketing literature). The test results were surprising. Although such increases of sales can be quite normal in split testing, I did not think that testimonials would make such a difference (and indeed put off testing them, thinking they were irrelevant). The increase in revenue was very substantial.

Any lessons which can be derived from your test?

Social proof is important, and it is important to test everything. I may try putting some small pictures next to each testimonial to see if this improves things. [Editor’s note: do that! Our previous split tests show that human pictures can potentially double conversion rates]

How valuable was Visual Website Optimizer for this test?

Visual Website Optimizer has been invaluable. You pay for the service once, but the increase profits and revenues continue into perpetuity. Through the use of several iterations of tests, we have increased sales threefold.

Founder and Chairman of Wingify.

Comments (7)

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  1. A/B testing is something you don’t think you need it until you test it. I’ve been wrong many times guessing on what page will convert better, so yes, its worth the time and money!


  2. Great case study. I used to work at WikiJob and was involved in some of the VWO A/B tests prior to this one and its amazing how much we managed to improve the conversion rate of this page thanks to VWO – one of the most useful online tools I’ve ever worked with.

  3. I’ve long been a believer in customer testimonials, and this is a wonderful example case study. Thanks for posting it!

  4. That is great insight. I don’t like to see testimonials on websites. The ones you used doesn’t offend me though, I actually believe them. Maybe it’s an idea to test simple vs ‘loud’ testimonials.

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