We need to know how many times he thinks it happens first.
First we need to hear from him how many times it happens a game, then we'll check for it when the season rolls around.
Yup. Not that we'll ever get a number, of course.
If it's too high he'll be wrong.
If it's too low, he'll be contradicting himself.
It was a sucker's bet. If he picks a number high enough to prove Rondo likes to do it then he'll be way over.
Since the stakes could end up being as high as a few TPs I'll point out that holding the ball for the last shot at the end of the quarter isn't evidence that he likes to do that, you have to have seen enough games to know that all teams do that to be eligible to play. You'd also have a lot of work to do to claim that stretching out possessions at the end of a game where we have a small lead is proof he likes to do it, that would be something called "strategy".
So, game in and game out, a good estimate of how often he does it out of his 60 or so possessions that aren't the last possession in a quarter or in the last few minutes of a close game. I'd expect it to be a large enough number that you could reasonably claim it's evidence that he likes to do that. Simple enough.
By the way, I'll double up on the issue and make the same "bet" with CoachBo. How many of the 60 or so possessions described above (not the end of the quarter or end of a close game) does Rondo hold the ball for 12+ seconds and then throw the ball to someone for a last second shot-clock beater? Realistically, since he's claiming 12 seconds and not 20 he has a fighting chance. But I'll take the bet anyways on the chance that his number's off. Waiting to see him tell whoever counted the times Rondo actually did that in a game that they were trying to use "sabermetrics" or "bogus numbers" would be worth it.