Post#2 » by J_T » Tue Dec 3, 2019 6:15 pm
Not sure what hard terms means. Does it mean you want formula or you want some kind of an interpretation of formula that's easier to understand? I'll try to put it together by using a player as an example and make the calculation.
Luka Doncic had BPM of 4.1 and VORP of 3.6 last season. VORP is calculated from BPM like this:
VORP = 4.1 - (-2) x 2318/3936 x 82/82 = 6.1 x 0.589 x 1 = 3.59
4.1 is his BPM
-2 is value of replacement player
2318 is number of minutes Luka played in the season
3936 is number of all minutes team played, 3936 = 48x82
82/82 because it's after 82 games
This season at the moment his BPM is 14.2 and VORP is 2.7
VORP = 14.2 - (-2) x 648/912 x 19/82 = 16.2 x 0.71 x 0.23 = 2.67
He played 648 minutes, team played 912 minutes, it's after game 19 of 82.
So as you can see VORP is getting larger as the season progresses for good players.
BPM is value of the player per 100 possessions. It was estimated that replacement level players have BPM value of -2 and average player is 0. So it's value against average player pretty much. The value is per 100 posessions, while VORP takes playing time into consideration and if you play a lot, your VORP will be higher. In a way VORP is the actual contribution of the player, while BPM is rate of contribution. Like for example points per 36 minutes vs points per game (or even better VORP would be more like... how many points has player scored in the season above number of points a replacement player would have scored).
What does the value actually represent? Well... in a way it's estimating fantasy points that player is producing. Not exactly of course, but I think it's the simplest way to say what it represents. Because it's not actually representing points scored as many think. The calculation of BPM is including a lot of different stats, points, rebounds, assists, steals etc. So it's pretty much some sort of fantasy value, compared to average/replacement player in the league.
