Downtime may grab headlines, but slow website performance is the silent-but-deadly #1 enemy

When I got back to my desk on Monday morning, I had not one, not two, but eight different emails from colleagues, sending me the same article about the Black Friday outages suffered by JC Penney and American Eagle.

I’m not surprised by this (the emails, I mean, not the outages). Spectacular site outages are the most visible form of IT failure, and, like car crashes, they get the most media attention.

But if we look at the results from Black Friday, while the spectacular car crashes of JC Penney and American Eagle may attract the attention, the real revenue killer is still site speed. But you won’t read headlines about this.

Site speed and site performance are not sexy and spectacular. It’s hard to get an editor excited about running a story with a headline like “An ecommerce site took 12 seconds to load from my house, so I got frustrated and went to a competitor.”

Yet my esteemed colleague, performance expert Lenny Rachitsky, has gone on the record (if Twitter is considered the record) as saying “Downtime is better for a B2C web service than slowness. Slowness makes you hate using the service, downtime you just try again later.”

A tale of two ecommerce mega-sites

To elaborate on this point, let’s compare with one of its competitors,

Website Availability Page load time (seconds) 100% 21.186 99.10% 7.231

According to this news release from performance monitoring company WatchMouse, JC Penney’s website was down for a total of 6 hours and 42 minutes on Black Friday. This is definitely something that JC Penney should be — and no doubt is — concerned about.

But let’s look at Macy’s, which had no downtime issues over the holiday weekend, but whose home page takes an incredible 21.186 seconds to fully load, compared to JC Penney’s passable load time of just over 7 seconds. If we look at the stats on the direct relationship between performance and revenue, and apply the formula that a 1-second performance improvement nets out to be about a 7% increase in conversion, we can deduce that Macy’s slowness is, quite arguably, a much greater revenue-killer than JC Penney’s one-off downtime issue. A relatively slow site like might have lost upwards of 30% of its potential revenue this weekend to competitors, due to its poor performance.

There’s also the long-term effect of slow performance. A 1-second delay equals a 16% decrease in customer satisfaction. This dissatisfaction leads to fewer return visits and negative word of mouth. In fact, joint research by Microsoft and Google found that the cost of slowness increases over time and persists for weeks even after site performance is improved.

Users brush off isolated downtime incidents. They don’t brush off the lingering effects of slow page speed.

And yet, given all this, JC Penney made headlines. Macy’s did not.

Right now, site downtime represents the single greatest fear of all IT professionals. Given the massive potential losses caused by slow site performance — a silent and deadly conversion killer — I suggest that sub-par page load times share that top spot.

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