Downtime vs. Slowtime: Which Hurts More?

The AWS outage of February 28, 2017 — which lasted four hours and affected almost 150,000 companies, including a significant number of online retailers — was, not surprisingly, dissected to bits.

Downtime is horrifying for any company that uses the internet as a vital part of its business (which is to say, most companies). It was almost exactly one year ago in March 2016 that Amazon (the retailer, not the service) famously went down for 20 minutes. Those 20 minutes may have cost the company $3.75 million in lost sales.

That’s a big number taken by itself. No company wants to think about losing millions in revenue. But it’s a drop in the bucket for a company with a net revenue of more than $125 billion in 2016. While Amazon assuredly takes pains to avoid outages, the company also goes to great effort to manage the day-to-day performance (in terms of page load) of its retail site. That’s because Amazon knows that page slowdowns can cause at least as much harm as downtime.

There are three metrics that are hit harder by slow page loads:

• Abandonment rate.
• Revenue.
• Brand health.

Let’s take a deeper dive into the data behind each of these metrics.

Visitors More Likely to Permanently Abandon Slow Sites Than Unavailable Ones

If a website is temporarily down, there’s a reasonable chance you’ll try again later if you’re motivated to track down whatever it was you were interested in finding on that site. But if a website or app is consistently laggy (read: many popular media sites), eventually, you just sort of drift away.

Anecdotally, this makes sense — and there’s research to back it up.

In one of the only studies (if not the only study) of the impact of outages versus slowdowns on abandonment rates, Akamai found that sites that went down experienced, on average, a permanent abandonment rate of 9 percent. Sites that suffered from slow performance experienced a 28% abandonment rate — an increase of more than 200 percent.

This isn’t to say that site outages are nothing to be concerned about. A 9% permanent abandonment rate is extremely detrimental to your business. And a 28% abandonment rate is even worse.

Slow Pages Could Have Twice the Impact on Revenue That Site Failures Do

This finding comes from a study that, to the best of my knowledge, is the only study that compares revenue losses due to downtime with losses due to page slowness. TRAC Research surveyed 300 companies and found that the average revenue loss for an hour of downtime was $21,000. For the same set of companies, average revenue loss due to an hour of performance slowdown (which was defined as response times exceeding 4.4 seconds) was much less (just $4,100).

Looking at just these two sets of numbers, outages seem like a bigger source of concern. But wait. According to this same survey, website slowdowns occurred ten times more frequently than outages. In other words, according to this research, slow-loading pages could have twice the impact on revenue that site failures do.

Slow Sites Suffer More Damage to Brand Health

Unless your site experiences frequent and noticeable outages, occasional failures won’t undermine your brand. Most users accept sporadic downtime as part of the reality of using the web. They’re less forgiving, however, if your site is routinely slow.

First impressions matter — and they happen faster than you might think. According to one study, we form our opinion of a website within the first 50 milliseconds. And once we’ve formed that opinion, it colors how we feel about a site’s credibility and usability, ultimately affecting whether or not we choose to make a purchase on that site.

A few years ago, I directed a neuroscientific research project in which participants were asked to complete transactions on an e-commerce site using mobile devices. Some participants experienced normal speeds, while others experienced load times that were artificially throttled with a 500-millisecond network delay. Participants believed they were participating in a standard usability/brand perception study, so they had no idea that speed was a factor in the tests.

After each set of tests, researchers conducted exit interviews with the subjects, who were asked to give their general impressions of each site and company. The results were revealing. Some participants picked up on the slight deterioration in performance (calling the slower site “slow” and “sluggish”), but those who used the slower site also developed negative perceptions of areas unrelated to speed:

• Content (“boring”).
• Visual design (“tacky” and “confusing”).
• Ease of navigation (“frustrating” and “hard to navigate”).

In other words, the slower pages affected people’s perception of three important aspects of the site that are closely aligned with brand perception.

Preventing Outages Is Just One Piece of the Performance Pie

There’s no such thing as 100% uptime. Every site goes down eventually. The question isn’t “Will my site go down?” The questions are “When will my next outage happen?” and “How long will it last?” and “How much will it cost me?”

If your business is reliant on your site, then you most definitely should care about preventing outages. You should, of course, conduct load testing and performance testing, and you should have effective load balancing and failover systems in place wherever possible.

But protecting your site from failure is just one piece of the performance pie. It’s a big piece, to be sure, but there are others. You also need to:

• Measure your site’s performance.
• Correlate IT performance metrics (start render, load time) with business and user engagement metrics (conversions, bounce rate, session length) so that you know which IT metrics are optimal for your business.
• Monitor performance in real-time to ensure you’re hitting your optimal IT metrics.
• Drill down and find and resolve performance issues as they occur.
• Look for opportunities to further optimize your pages (hint: images and third parties are a great place to start).

Comparing outages to slowdowns is like comparing a tire blowout to a slow leak. One is big and dramatic and the other is quiet and insidious. Either way, you end up stranded on the side of the road.