This is one such Strava study regarding Boston Qualification.
"Male [Boston] qualifiers ran 15 percent of their training runs at marathon pace or faster. For the other 85 percent of their miles, they ran slower than the qualifying standard pace, signaling that they only cranked up the effort for important workouts. In comparison, male non-qualifiers may be going too hard, too often. Fifty-seven percent of their runs were done at their BQ marathon pace or faster."
Unsurprisingly, taking of running selfies is also negatively correlated with Boston Qualification.