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**Calculation**

*Step One: Calculate uPER*

uPER=(1/M)*(TP+(2/3)*A+(2-factor*(TA/TFG)*FG)+FT*0.5*(1+1-(TA/TFG)+(2/3)*(TA/TFG))-VOP*T-VOP*DRB%*(FGA-FG)-VOP*0.44*(0.44+(0.56*DRB%))*(FTA-FT)+VOP*(1-DRB%)*(TRB -ORB)+VOP*DRB%*ORB+VOP*S+VOP*DRB%*B-PF*((LFT/LPF)-0.44*(LFTA/LPF)*VOP))

Where M=Minutes, TP=Three-Pointers, A=Assists, TA=Team Assists, TFG=Team Field Goals, FG=Field Goals, FT=Free Throws, T=Turnovers, DRB%=Defensive Rebound Percentage, FGA=Field-Goal Attempts, FTA=Free-Throw Attempts, TRB=Total Rebounds, ORB=Offensive Rebounds, S=Steals, B=Blocks, PF=Personal Fouls, LFT=League Free Throw, LPF=League Personal Fouls, LFTA=League Free-Throw Attempts

*Step Two: Calculate factor and VOP*

Factor=(2/3)-(0.5*(LA/LFG))/(2*(LFG/LFT))

Where LA=League Assists, LFG=League Field Goals, LFT=League Free Throws

VOP=LP/(LFGA-LORB+LT+0.44*LFTA)

Where LP=League Points, LFGA=League Field-Goal Attempts, LORB=League Offensive Rebounds, LT=League Turnovers, LFTA=League Free-Throw Attempts

*Step Three: Adjust for pace and league to calculate PER*

PER=(uPER*(LPace/TPace))*(15/LuPER)

Where LPace=League Pace, TPace=Team Pace, LuPER=League uPER

**Explanation**

As loyal readers of my articles may have noted, I'm a fan of using PER as a baseline measurement of a player's performance because it's a metric that is both easily accessible and whose output is easy to understand.

In John Hollinger's words, "The PER sums up all a player's positive accomplishments, subtracts the negative accomplishments, and returns a per-minute rating of a player's performance."

To be perfectly honest, there is no way that I can possibly sum up the calculation of Hollinger's most famous statistic. If you really want to understand where he got each number from, I would highly recommend reading his books.

The basic idea though is that PER spits out one number to represent a player's performance. It accounts for per-minute performance and how a team's pace of play compares to the league average.

Hollinger set up the system so that a PER of 15 is the league average number.

As you'll soon see in the limitations section, although this is the single best measure to use when describing a player's overall performance because of it's scaled appearance, it does lack in some areas.

**Limitations**

As much as PER takes into account, it still has its flaws, as does any stat.

Hollinger himself won't deny that the system he has set up doesn't take into account anything on the defensive side of the ball other than blocks and steals. Although both are important measures of defensive play, they are by no means an all-encompassing way of valuing a player's defensive contributions.

A second major flaw is the rewarding of inefficient shooting. Dave Berri, in *The Wages of Wins*, writes the following:

Hollinger argues that each two-point field goal made is worth about 1.65 points. A three-point field goal made is worth 2.65 points. A missed field goal, though, costs a team 0.72 points. Given these values, with a bit of math we can show that a player will break even on his two-point field-goal attempts if he hits on 30.4% of these shots. On three-pointers the break-even point is 21.4%. If a player exceeds these thresholds, and virtually every NBA player does so with respect to two-point shots, the more he shoots the higher his value in PERs. So a player can be an inefficient scorer and simply inflate his value by taking a large number of shots.

A third and final major flaw is that you can routinely find players who have astronomical PERs due to the fact that they have played extremely limited minutes. Hasheem Thabeet's PER is 19.1 right now, for example. While that's not an astronomical figure, it is for Thabeet.

You'll find one more way that PER can be improved on the next slide.

**Example Usage**

"LeBron James has a PER of 33.33 this season, a mark that would beat Wilt Chamberlain's all-time record of 31.84 if it was maintained throughout the rest of the 2011-2012 campaign."

*How I interpret this sentence: *LeBron James is really good.