Late last year the team at the Financial Times launched a redesign that focused specifically on web performance and improving the user experience. And so in a post detailing their findings, James Webb writes about how this design impacted their business:
We wanted to keep page load time to an absolute minimum; our target was to become the fastest site in the publishing industry.
To emphasize the importance of a faster website to key internal stakeholders, we had to understand the true impact site speed had on user engagement. Fortunately, our analytics team had developed a sophisticated internal engagement metric that accurately predicts the likelihood of renewing a subscription.
Through a rough a series of A/B tests, we slowed the site down to see how site speed correlates to the loss of engagement and revenue. Test results showed that for every one-second increase in speed, our engagement score increased by 5%. In subscription and ads inventory, this translates into millions in revenue. Speed therefore became a principal element of the site.
If you find case studies like this useful, see WPO Stats.
Source: CSS Tricks Financial Times Redesign