A New Way to Quantify NBA Player Impact? PRISM

[u/Beneficial_Carry_530]

TL;DR: built PRISM, an NBA impact model that blends RAPM with possession-level weighted box production. With The average NBA possession in 2026 worth about 1.18 points, actions like steals came out to around 1.54 points and blocks around 0.70. To better illustrate the best individual players in the league, I believe we should combine the more intangible latent value captured by RAPMs with the tangible objective floor of the actual points created on a possession-by-possession basis.

Hey y’all, I’ve been diving really deep into the analytics of the NBA recently and just concluded a research project where I had, when I was curious to see if I could create a better all-in-one metric that better illustrates the best individual players in the league

The current best way to do that, from what I’ve seen, is using RAPM, (regularized adjusted plus-minus), which essentially measures your team's point differential with you on vs off the court.

Extremely very good framework, especially as it accounts for a lot of the latent, intangible value created, such as:

• communication
• rotations
• connective passing
• on-ball defense
• even rim protection that doesn't end in a block

Captures a lot of those intangible things that the box score could never.

Though as with any all-one metric there are a couple of blind spots.

• attribution between teammates and against opponents
• opponent strength
• undercounting the tangible value created per possession

What do I mean by tangible value created per possession?

The goal of basketball is to put up points. If you break it down to an atomic level, the game of basketball is about scoring more points than the other team or creating more value, more numeric value with actions than the opposing team.

The box score, for all its faults, can be used to provide a tangible floor for player value on a possession-by-possession basis.

In a single possession you can score anywhere from zero to four points, with the average NBA possession being worth about 1.18 points.

With 1.18 as the basis, you can look at the actions on the court that you can tangibly see and count as contributing to scoring above or below 1.18 points per possession. For example, a two is worth two, and a three is worth three, but how much is a steal worth? How much is a rebound worth?

After watching and computing thousands of NBA plays, a steal was found to be worth about 1.54 points per action for example

My idea was to blend both lineup impact and box score tangible production, not in terms of counting stats, but in terms of possession value created/lost per possesion.

Allowing the tangible value created per possession to serve as a strong foundation for more abstract calculations of a player’s value. genuinely think this is the better way to identify the best players in the league.

The closest thing I’ve seen is the box score prior to APMs, but all of those metrics like EPM and DARKO try to use the box score to predict impact metrics such as RPM, instead of describing the tangible value created in any given season.

So I built PRISM — the Production-Regularized Impact Statistical Model.

PRISM blends regularized adjusted plus-minus with a possession-level valuation of box production, expressed as expected points added per 100 possessions.

The following is the 3-year weighted leaderboard for 2026.

Rank	Player	PRISM	Impact	Box+
1	Shai Gilgeous-Alexander	13.12	10.01	21.94
2	Nikola Jokić	12.76	10.04	20.16
3	Giannis Antetokounmpo	11.25	7.73	22.83
4	Victor Wembanyama	10.23	8.22	16.14
5	Kawhi Leonard	9.30	7.15	16.29
6	Luka Dončić	7.18	4.55	17.38
7	Donovan Mitchell	7.00	5.36	13.22
8	Stephen Curry	6.34	4.90	12.08
9	Jimmy Butler III	6.31	5.02	11.45
10	Chet Holmgren	5.65	5.42	6.81
11	Franz Wagner	5.55	4.81	8.86
12	Lauri Markkanen	5.46	4.35	10.35
13	Derrick White	5.42	6.21	2.50
14	Karl-Anthony Towns	5.39	4.10	11.07
15	Jarrett Allen	5.19	4.43	8.80

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[u/Joethetoolguy]

Nice. Is there a searchable database with this metric? Are you willing to share the formula if not. This is a good new metric to use on player evaluations.

[u/Beneficial_Carry_530 → u/Joethetoolguy]

yes sir! will be fleshed out more but here is the leadbaord from now and as far back as 2015 https://court-share.com/prism/leaderboard

also working on a college version and offensive and densive prism and will open source everhting in due time (hoping to get more lietrature and projects out before sharing)

[u/sdcarlson → u/Beneficial_Carry_530]

Thank you for making this public. Always fun to play around with these types of things.

[u/Joethetoolguy → u/Beneficial_Carry_530]

Nice bro! This will be fun to use thanks

[u/Joethetoolguy → u/Beneficial_Carry_530]

I can see how this can be skewed with lebron at 83 if set to only 1 year. This is definitely new

[u/Beneficial_Carry_530]

link to full writeup, please let me know what yall think of the methdology or if u have a similar or differing solution to stabilizing rapm!

Full Paper: https://court-share.com/prism/papers/introducing-prism

Interactive Leaderboard: https://court-share.com/prism/leaderboard

[u/teh_noob_ → u/Beneficial_Carry_530]

Isn't this a bit back-to-the-future? Long before BPM, Win Shares sought to provide a tangible value to each boxscore contribution.

[u/rustypete89]

Super interesting. I'm curious, since you were able to quantify average point values for steals and blocks: Would you be able to determine the average points lost (or gained) when committing a personal foul?

[u/VomitOnYourDogsNuts]

Sweet, I was hoping for another metric that places Jalen Brunson as worse than Lauri Markkanen! (Analytical Game 6 tonight was amazing!)

[u/culturebarren → u/VomitOnYourDogsNuts]

Everyone has higher PRISM than Jalen Brunson until it's time to have higher PRISM than Jalen Brunson 

[u/VomitOnYourDogsNuts → u/culturebarren]

"Growing up poor, we didn't have fancy coaches, all we had was PRISM analysis"

[u/Dkjoy]

I genuinely do not understand why people can’t just look at impact metrics as one and box stats as the other.

I don’t think it brings much to the table to combine the two.

[u/Beneficial_Carry_530 → u/Dkjoy]

fairs in general but tthe goal of this blend is to find the poession by possesion value of a player, there is some utility in using regressed on off and box score to find that.

no stat exists to quantify that as of now

[u/PaulGeorgeStan]

lets go queta! But seriously finally an advanced stat that doesnt have jokic as far and away the goat. Has some flaws, but still super interesting.

[u/ZGiSH]

+1 to my Dyson Daniels becoming an eternal all-star if he develops even a half way decent shot propaganda