Nylon Calculus: How many possessions will the new shot clock rule impact?

Yesterday, it was announced announced via twitter that among other ideas, the NBA is planning on changing the rules regarding the resetting of the shot clock after offensive rebounds. Previously after an offensive rebound, the clock would reset to a full 24 seconds. According to the proposed rule change the shot clock will now reset to 14 seconds, shaving a full 10 seconds off of the amount of time the rebounding team has to try and score again.

The rule is presumably going to be implemented to prevent teams from burning an excessive amount of clock late in games after grabbing an offensive rebound with the lead. This announcement does beg the question of how often does this actually occur though, given that it is widely held and observed that most offensive rebounds result in either a putback or quick spot up 3.

The following is a breakdown of how long possessions after offensive rebounds lasted ;ast season.

Indeed, the numbers hold with the prevailing logic that possessions after offensive rebounds tend to be incredibly quick. Over 30 percent of offensive rebounds result in putbacks (the 0 Duration value on the graph) and 75 percent of offensive rebounds result in a possession that is five seconds or less. Only 6 percent of all offensive rebounds resulted in possessions that are 14 seconds or greater last year. Given that the league average for offensive rebounds was the lowest ever this past season at 9.7 per game, this rule would apply to roughly half a rebound per team per game last year.

That is not to say that changing the shot clock rules is without purpose. Nobody wants to watch 10 men stand around while one guy dribbles, and if the new rule results in better TV, than it’s mission accomplished. Ultimately though, given that we are only talking about a few seconds per game, the affect that this will have on actual game play will be minimal.