When the researchers [in San Francisco] sat by the call handlers and noted down what was happening - they found 30% of calls coming in from mobiles were accidental butt-dials, also known as pocket-dials.
As well as being time-consuming taking the call, the impact of butt-dials doesn't stop there.
Each one requires further attention - after all, the 911 handler doesn't know if it was a mistake, or someone trying to call for help but unable to talk at that point.
And so, all butt-dials are followed up. In the sample period, it took an average of one minute and 14 seconds to get back to people and determine the call was a mistake.
In a survey of handlers at the San Francisco 911 centre, 80% said chasing these calls back was a time-consuming part of their already overstretched day.
About 39% said it was the single biggest "pain point" they had in the job.
October 5, 2015
Butt dials 30% of mobile calls to 911 in S.F.