When attending an international conference, Robert M. Ewers, professor of ecology at Imperial College London, found that 34 interesting talks lasted, on average, a punctual 11 minutes and 42 seconds. In contrast, the 16 boring ones he recorded dragged on for 13 minutes and 12 seconds (thereby wasting a statistically significant 1.5 min; t-test, t = 2.91, P = 0.007).

That means that for every 70 seconds that a speaker “droned on,” the odds that their one-person drama had been boring all along doubled.
When confronted with the question whether he is going to follow this correspondence up with another study to demonstrate that it can be replicated, Ewers said: “I’ve seen people on Twitter talking about replicating the study, but this is not something I’m going to follow up on – too boring.”