Premium shirt retailer Charles Tyrwhitt has seen a 30% increase in conversions year-on-year after making multivariate testing (MVT) a major part of its optimisation strategy.

The company relaunched its website in October 2010 and since December that year has carried out regular tests with Maxymiser to confirm its assumptions, test variants and back up user research done ahead of the relaunch. As such online sales now account for 70% of the retailer’s overall revenue.

Jennie Blythe, head of web development and trading at Charles Tyrwhitt, said MVT is now an “essential component” of what the company does. “There’s no point investing time and resource in customer acquisition and SEO to drive customers to a site if you are going to neglect them once they’re there,” she said.

The initial focus for testing was on the checkout page to determine the optimum user journey through the process.

Based on that test the retailer achieved a 4% uplift in the conversion of customers who moved through to the next page of the checkout, which Blythe said was a “significant sales improvement”.

Tests were not just focused on the sales page though. In order to corroborate the user research it did as part of the redesign process, the company put together a task model for how people shopped for shirts and out of that research it was revealed that fit was most important, followed by a number of secondary attributes such as collar size and cuff type.

The company set up a six-week campaign based on 64 test variants across four components to determine the optimal order for the left hand navigation function, which categories should be expanded and the colour the bar should be.

This led to a 3% increase in listings page arrivals, a 13.7% rise in purchases and a revenue uplift of 20% per generation.

One of the most surprising outcomes, according to Blythe, was the optimum position for product images. It carried out a test early on to determine the impact of putting product images on the righthand side rather than the left.

As a result, conversions increased by around 8%, so this format has now been implemented across all sites (see picture below).

“The perceived wisdom would have been to have it on the left so the fact the right hand variant won out was a bit leftfield,” she said.

The testing also highlighted cultural differences across Charles Tyrwhitt’s sites in the UK, Germany and the US, which shows the need to carry out tests across all regions rather than relying solely on the data from one country to inform another.

The company tested the difference in user behaviour when they were directed to a department page and a category page.

She said, “In the US and Germany the differences are really quite pronounced. To the extent where we don’t offer category pages in Germany any more, we just go straight through to the listing.”

Charles Tyrwhitt is currently running tests (with another provider) to introduce more personalisation on the site. It will look to retarget information based on consumers’ choices depending on what they’ve looked at, what they’ve bought and how often they come back.

As an example she said, “If a customer has bought a classic fit shirt, which is our most popular style, we won’t show them tailored shirts, so we’ll give people more of what they want.”