While watching AMC’s Halt and Catch Fire, I learned about the “Doherty Threshold”, a discovery from a 1982 IBM report called “The Economic Value of Rapid Response Time”. The report is old gold and reads like a modern day #webperf article.

When a computer and its users interact at a pace that ensures that neither has to wait on the other, productivity soars … and its quality tends to improve. Few online computer systems are this well balanced; few executives are aware that such a balance is economically and technically feasible.

Chart illustrating

As illustrated by the chart, a sub-400 millisecond response time creates a dramatic increase in users’ interactions at all different skill levels. As the TV show dramatizes, under 400ms an activity is addicting, over 400ms it’s painful and users’ attentions begin to stray.

“I wonder if that has any modern day web design parallels…” he guffaws into a Grape Nerds® Slushie from Sonic.