What predicts when an Olympic record will fall?

It turns out that if the current holder also set the record in the past, the record is more likely to be broken at the next games.

If the current Olympic record is also the world record, it is less likely to be broken in the next games.

A change in the number of countries competing in an event  is also an important indicator of whether the record will fall.

And most surprising of all, the percentage by which the existing record improved on the first Olympic record, is also a significant indicator.

There is more here, and the original paper is here.  For the pointer I thank Michelle Dawson.