(Randball) Behind the Stats Curtain: PER

6 Feb

My latest guest feature at the Star Tribune’s Randball blog.


Behind the Curtain

In which Brandon from World of B introduces and explains complicated-seeming statistics in an effort to enlighten the masses that have neither the time nor inclination to do so themselves. Apologies to the hard-core statheads who will likely be offended by the occasional over-simplifications.


Featured stat: PER (NBA)

What does it mean? Created by John Hollinger, PER stands for Player Efficiency Rating, which means exactly what it says. When spoken aloud, most people say each letter separately as per acronym tradition, but I’ve heard others shorten to “per.” I recommend the former to avoid sounding like a cat.

What does it measure? Essentially every basic stat that can be measured (except +/-). PER attempts to be an all-encompassing number that shows the most efficient individual players on a per-minutes basis (i.e. a player can have a high PER even in limited time). The final numbers are normalized to make 15 league average. Fun fact: the Wolves have three players with above-average PER.

Not like I care, but how is the number equated? I briefly considered showing the full equation for hilarity’s sake, but then worried that if I didn’t encode it correctly, the figures would react poorly with the Strib backend server and result in the entire website melting down. Just know that essentially every statistic is included and given a relative value of importance. Please don’t ask me to elaborate. I studied the equation for about ten minutes straight and went cross-eyed for the remainder of the day.

Basically: PER adds all the positives, subtracts the negatives, weights for importance and standardizes for pace of play.

Can it measure heart? Kind of! I mean, even the slothful-est, least-caring of players can score the rock providing they are gifted enough and chuck-happy, but pure scoring itself won’t result in a top-notch PER. Rebounds, assists, turnovers and missed field goals, among other stats, are key factors. For instance, Carmelo Anthony is 9th in scoring this season, but 33rd in PER, likely due to a poor FG%.

Will it make me question my heroes? Probably not. Michael Jordan is tops in career PER, followed closely by – surprise? – LeBron James. Dwyane Wade is 6th overall, which proves once and for all that a strategy of dribbling the ball into the lane and purposely barreling into any defender that doesn’t have his feet set is historically effective. More players should try that.

Other career PER notes: the immortal Neil Johnston is 9th, and hero of all white people Larry Bird is a surprisingly low 18th. Since there is no obvious reason for his low ranking, let’s blame the mustache.

Is it widely used/accepted? PER is probably the most widely cited of all complicated geeky NBA stats, though the hard-corest of us can point to a couple other interesting numbers (Win Shares and 82games’ Simple Rating being two). Hollinger is a prominent ESPN scribe and his stats have their own page on ESPN. Your dad hasn’t heard of it and I wouldn’t recommend bringing it up to him unless you’re looking to lose the last shred of his respect for you, but your friends probably dig PER.

How valuable is it? Very. Nearly all-encompassing. PER is one of the most essential statistics out there, with two limitations that need to be recognized:

(1) The only defensive attributes are rebounds, steals and blocks. Shutdown defenders such as Shane Battier and Corey Brewer aren’t given the credit they deserve, PER-wise, and likely never will. (2) The main complaint with PER is it arbitrarily weights each value. I agree but also feel such an opinion is full-on nitpicking territory. PER is not perfect (no basketball stat ever will be) and it has its flaws, but it’s a vast improvement to scanning the traditional leaderboard. Promise.

If you still aren’t convinced, please note that Jonny Flynn’s current PER is 6.8, ninth worst in the league. Case closed.

Final Grade: A-


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