Slow connections: when every click waits

Under about a tenth of a second, a response feels instant. Under a second, your train of thought survives. Past ten seconds, your attention wanders off.

Those three limits are usually credited to the usability writer Jakob Nielsen, but he was summarising¹ work by Robert Miller in 1968 and by Stuart Card and colleagues in 1991. In 1982 two researchers at IBM, Walter Doherty and Ahrvind Thadani, found that programmers got twice as much done² when the computer answered in 0.3 seconds instead of 3: about 371 transactions an hour instead of 180.

When nothing seems to happen, people do the natural thing and click again. Analytics companies even have a name for it, the “rage click”. On a slow connection, that second click can order twice, pay twice, or send the person somewhere they did not mean to go.

According to the International Telecommunication Union, 2.2 billion people⁶ are still offline, and 96% of them live in low- and middle-income countries.

Coverage is not the main problem; price and quality are. In nine of ten low-income countries, a modest 5-gigabyte mobile plan costs more than a tenth⁷ of a month’s income. Every heavy image is paid for by the person who downloads it.

It is close to home, too. In the United States, about 24 million people lack fast home broadband, including 28% of rural residents, and among households earning under $30,000 a year, about one adult in three⁹ is online only through a phone. And everyone has had one bar of signal on a train.

Some of the best-known figures about speed are weaker than they sound, and it is worth knowing which.

“53% of mobile visits are abandoned after three seconds” comes from a 2016 Google report³ built on its own analytics data, with no published method. “Every 100 milliseconds costs Amazon 1% of sales” is a former engineer’s recollection⁴, not a published study. The direction they point is supported; the exact numbers are not.

The firmer targets today are Google’s Core Web Vitals⁵: the main content should appear within 2.5 seconds, the page should respond to a tap within 200 milliseconds, and nothing should jump around while it loads, all measured for three visits in four.

This tool changes how your clicks and taps land, and it catches pointer presses as well as clicks, so it works on prototypes that are drawn as a picture, such as a Figma prototype link, as well as on live pages.

A few apps listen for presses in ways no bookmark can reach; if nothing changes when you click, the app is one of them.