The author of the marathon paper explains the phenomenon he is observing, and then goes on to "reject that explanation" without attempting to do anything to control for it.
>For example, the 2013 Chicago Marathon provided pace teams for 3:00, 3:05, 3:10, 3:15, 3:20, 3:25, 3:30, 3:35, 3:40, 3:45, 3:50, 3:55, 4:00, 4:10, 4:25, 4:30, 4:40, 4:55, 5:00, 5:10, 5:25, and 5:45.T he institution of pace teams then could provide an alternative explanation for the bunching we observe at round numbers.
It would be easy to do, even. Restrict to marathons where the pace team spectrum is known to be of a specific type and see if the other spikes disappear. The author certainly has the data to do this, and isn't. That is suspicious.
There is one more reason for discontinuity around 4:00 - many amateur runners make a goal to run in 4:00 or less (hard but achievable) and reduce training intensity once they finished in 3:5x - 4:00.
That doesn't explain a discontinuity, and moreover, the effect of the pace runners has yet to be controlled for, so there is no more explanation required.
>For example, the 2013 Chicago Marathon provided pace teams for 3:00, 3:05, 3:10, 3:15, 3:20, 3:25, 3:30, 3:35, 3:40, 3:45, 3:50, 3:55, 4:00, 4:10, 4:25, 4:30, 4:40, 4:55, 5:00, 5:10, 5:25, and 5:45.T he institution of pace teams then could provide an alternative explanation for the bunching we observe at round numbers.
It would be easy to do, even. Restrict to marathons where the pace team spectrum is known to be of a specific type and see if the other spikes disappear. The author certainly has the data to do this, and isn't. That is suspicious.