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Measuring the Right Metrics for Web Performance Monitoring

Posted on 1.01.2013

Compelling content, reliability and performance lend themselves to an excellent overall user experience and the kind of metrics Web workers like, such as increased time-on-site, higher click-through rates and more. If a site is slow, however, users won't stick around to view (let alone interact with) content or ads. And, as we know, successful sites rely on ads and eyeballs.

Microsoft’s Bing did a study and found that a one second page delay cuts ad revenue per user by 2.8 percent. Add to that the proliferation of platforms for online viewing — PCs, tablets, smartphones — and the methods and challenges for measuring the true user experience get more complex. Since people want to have access from anywhere, the challenge becomes how to test and scale these different platforms for a consistent and responsive user experience.

Consider the breadth and scale of many consumer sites today (e.g. the amount of content, the frequency of updates, and the use of graphics and video). Then add to that the additional third-party applications that might also be part of the experience, such as embedded players, Facebook, comments sections, outbound links, etc. With that said, many website owners already have good Web performance monitoring tools in place, but some recent developments provide even better ways to measure the real viewer experience. 

A good analogy is that of flying measurements. One of the critical measures is the airspeed indicator, which measures the plane’s speed through the air. It’s a critical metric, which tells the pilot whether the plane has enough air over its wings to fly. But unlike the speedometer, it won’t tell you exactly how fast it’s going. That’s groundspeed, which is measured differently. Yet, both are needed to pilot a plane correctly. 

And so it is for website performance. For years, websites have been “piloted” using airspeed only.

Most websites today use monitoring services that provide an external perspective of performance by measuring network latency. Testing systems located in datacenters all over the world measure the amount of time it takes to download content from the company’s website. This continuously robotic sampling of a website’s responsiveness can tell website owners a lot about how well their sites are delivering content, but it doesn’t represent how well a user’s Web browser is actually assembling that content or how the user interacts with it.

But there are new industry standards and technologies that reveal performance more holistically — based on users’ true experiences. The World Wide Web Consortium (W3C) and major browser organizations recently agreed upon the Navigation Timing standard for measuring speed from the browser client.

“The browser itself saves timestamps from various events in the process of navigating to a page, including timestamps for the starting and ending of phases,” said Internet Explorer Program Manager Jatinder Mann, who is in the W3C working group.

Now implemented in the current versions of Internet Explorer, Chrome and Firefox, the Navigation Timing standard helps measure:

• Time to First Paint — the first point at which the user sees something other than a blank screen.
• Time to Interactive Page — when a page can be fully clicked, swiped and scrolled.
• Total User Experience Time — the total time a page takes to render and become usable.

These are important events in a page’s lifecycle because customer expectations of a website’s performance continue to increase. In 2006, studies found that users were willing to wait four seconds while a page loaded before they would abandon a site. By 2009, that time had dropped to two seconds, and users exited a site in droves at the three-second mark. Today, Microsoft reports that a miniscule difference of 250 milliseconds (that’s one-quarter of a second; if you just blinked, that took longer) is enough to give one site a competitive advantage over another.

Imagine you visit two sites, each with a page load time of five seconds. If site A starts delivering content in half a second and site B doesn’t start giving you content until four seconds, your perception of site A will be much more positive even though both sites have the same overall response time.

If you can monitor both metrics, you stand a much better chance of delivering a better viewer experience, which in turn means greater revenues.

New tools are also becoming available to monitor these new metrics (on an ongoing basis) to see what is happening deep inside the browser, alerting companies when critical performance metrics like Time to First Paint are slow. Such a delay might be the result of an unexpected change in a given page’s construction or a failure in a third-party’s ad or JavaScript widget. With this information, companies can better understand if they’re hitting the right service level agreements (SLAs) for user experience.

By using metrics, such as Time to First Paint and Time to Interactive Page, broadcasters can better understand when content (especially third-party content from advertisers) impacts user experience. Ad failures can sometimes feel like a game of “whack-a-mole.” Sometimes it can be difficult to know which failures to focus on, and how to enforce performance standards from advertising partners. The reality is, not all failures are the same, and it’s important to discern those which truly impair or obstruct a user. Because many ads require JavaScript, having visibility into the events governing a Web browser’s processing of a page is crucial. Although you may not be able to control when an advertisement failure impairs the user experience of a Web page, monitoring at the user experience level can be used to enforce performance service levels with advertisers. Receiving timely notifications of failures allows you to immediately take corrective action against offending advertisers. And long-term trend data can be useful in negotiating rates, as well as in making trafficking decisions. Ultimately, proactive management of troublesome advertiser relationships helps protect your brand and revenue.

So make sure you’re looking at your website’s responsiveness in terms of both network latency and user experience, otherwise you’re monitoring only half the performance.

About the Author: Aaron Rudger is a senior marketing manager for Web performance at Keynote Systems, a leader in mobile and website testing and monitoring.


QUICK HIT!Web Performance in Focus

Keynote’s News Performance Index, which measures and benchmarks the home page performance of the top general media and financial news sites, illustrates just how significant the differences are in performance across these destinations in terms of user experience. For example, the overall time it takes to render and use the Fox Business home page is nearly 37 percent longer than that of the Forbes home page. However, the amount of delay a user experiences before the Fox page begins rendering is 80 percent faster than Forbes.

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