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The Goals

  • Reduce mobile latency to increase page views and engagement

The Approach

  • Used domain sharding to load 100+ images at once on mobile sites
  • Leveraged responsive design to deliver the right site version to the right device

The Results

  • 80% greater user engagement
  • 500% faster page load time
  • 5X more pages per session


Published November 2016

The world doesn’t stop when people are on the go. People always want quick, relevant information, which is why Sinclair Broadcast Group does their best to connect people to the news they care about — fast — when they're on mobile devices.

Sinclair runs over 180 television stations in 90 markets. They’re the leading local news provider in the United States. As they’ve grown, the company has amassed a large number of digital properties, including websites, mobile sites and mobile apps.

Shifting strategies for a growing mobile audience

Not long ago, 45% of people visiting Sinclair’s news sites were on mobile, but from 2014 to 2016 that number jumped to 70-80% in some markets. Sinclair began dedicating more attention and resources to their growing mobile audience. “If our audience is more often on mobile than on desktop, we need to make sure that we’re serving this audience well, because it’s only going to get bigger,” says Kristi Gray, Director of Product at Sinclair Broadcast Group.

Using Analytics to understand user behavior

Sinclair knew that people had different expectations for speed on mobile. “There’s a lot of evidence to show that if you increase the speed of your site, you’ll get better retention rates and usability,” says Michael Bouchard, Senior Director of Technology. “If it’s easier for people to view a page, they’ll view more pages.” 

A quick look at Google Analytics revealed a high bounce rate, a sign that visitors to Sinclair’s sites were quickly leaving. “When we recognized that we were getting high abandonment rates on a number of our mobile sites, we looked at our load times. We then became obsessed with getting those numbers lower,” explains Ben Miller, Vice President of Digital Products at Sinclair Digital.

Measuring the metrics that matter

In late 2015, Sinclair contacted various mobile experts to see what metrics they should use and how best to measure them. They then asked DoubleClick to discuss mobile site speed. The DoubleClick team analyzed Sinclair’s mobile properties and shared ways to reduce load times and increase engagement.

Our meeting with DoubleClick took us from being not quite sure what to measure to knowing immediately. Within four weeks, we had everything addressed. And that was the key thing for us. We got a second set of eyes and advice for homing in on what really mattered.

Ben Miller, Vice President of Digital Products, Sinclair Digital

Giving users an ideal mobile experience

One key way Sinclair increased mobile speed was through a process called domain sharding. On a mobile page with 100 images, for example, a mobile browser could load only six at a time. This led to high mobile latency. By sharding the 100 images across different domains, Sinclair could load everything in parallel.

Sinclair also created a responsive web experience, which directed viewers to the desktop site when they were using computers and the mobile site when they were using phones. “When we know somebody's coming from a mobile device, forcing the entire desktop experience down to the mobile device isn’t optimal,” Miller says. “So we re-rigged our rendering engine to omit things that were unnecessary for mobile readers.”


With these two improvements, Sinclair’s average page speed increased 500%. User engagement increased by 80% and pages per session also went up by 5x.

Sinclair knows that mobile will continue to be important for their business.

We want to continue providing content to people where they are — and fast. People spend more time with their phones than they do with any other device. If we don't have a story for the user as it happens, we're too late.

Ben Miller, Vice President of Digital Products, Sinclair Digital