Statistical Analysis

Stat of the Week: What’s PDO? A Q&A with Brian King, the “Father of PDO”

In our “Stat of the Week” series, Jon examines non-traditional statistics. Emphasis will be placed on how the Oilers are performing according to each statistic.

In this installment of Stat of the Week, we’re looking at PDO. Simply put, PDO is the sum of a team’s shooting percentage and save percentage (PDO=S%+SV%). The idea behind PDO is that and a team should score on about 8% of its shots, and a goalie should stop around 92% of the shots he faces. This means that a team should normally have a PDO somewhere in the vicinity of 100 (92+8=100). So if a team has a PDO of 105, they’re probably getting some lucky bounces. And if a team has a PDO of 95, they’re probably suffering from a severe case of bad puck luck.

The “Father of PDO” is Oilers fan Brian King. He kindly took the time to answer a few of our questions, and we thank him for doing this.

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JON: PDO is often mistaken as an acronym. For those who don’t know the story, how did this stat come to be known as PDO?

BRIAN: The longer it goes on, the more humorous I find it because everyone has guessed what it “could” or “should” stand for. The absolute best guess anyone put forward was Pretty Dangerous Otter. The truth of the matter is that it doesn’t actually stand for anything. I needed a handle when I started playing video games online, and I liked the way PDO looked. Everyone always finds it disappointing that it does not stand for anything. Maybe I’ll put it up for a vote and let it permanently stand for Pretty Dangerous Otter.

JON: When did you first come up with PDO, and how was it first received?

BRIAN: Unfortunately, the website where I can first be credited with coming up with PDO is no longer available online. The site was called Irreverent Oiler Fans (IOF). Most of the big NHL stats that we all know and love today started on that small blog.  The blog was run by Vic Ferrari and had contributors such as former Oilers’ employee Tyler Dellow, Matt Fenwick and myself.  Corsi, Fenwick, and PDO all gained a lot of momentum there.

When I first looked at it I was actually only looking at individual players. The Oilers themselves had a horrible habit of paying guys with high PDOs and flushing guys with low PDOs for pennies on the dollar. Vic wrote a post about “throwing craps” in which he referenced a game where guys would throw dice and the hot streaks that would happen, and how somebody could be considered an incredible craps player when in fact he just threw the dice like anyone else but had outstanding results. He parlayed this into a table in which he had every individual player’s on ice event strength save and shooting percentages together. The purpose was to identify players who were at extremes in either statistic.

It seemed intuitive to me to combine them in case somebody had the bounces evening out at the other end of the ice. I tend to think every hockey player has gone through a stretch where no matter how hard they tried, and everything that they did right, the puck just wouldn’t go in for them at one end and then their goalie would let in a weak backhand from the slot ten seconds later.

JON: According to Wikipedia, PDO is “called SPSV% by the NHL.” Some people also call it “Percentage Determined Outcomes.” How do you feel about people wanting to change what PDO is called?

BRIAN: At first I found it really annoying. As time has gone on though, it doesn’t matter as much. I am sort of credited on the NHL website for it, but it would be nice if they at least linked to my twitter profile or something along those lines. After that though, it’s really not a big deal. As much as I would love for an NHL team to hire me, I really don’t see that being in my future, so the novelty of it is really all I have. It’s fun to be able to say I’m the guy who created it.

I received a signed copy of Bob McKenzie’s latest book from him for the few paragraphs that I was able to contribute to it, and I felt that was really cool.

JON: Do you think we should expect a team with an elite goalie or an elite forward to post a higher PDO than other teams that lack elite players?

BRIAN: Absolutely, but more so with an elite goalie. Elite forwards are only on the ice for 20 minutes at the most, whereas an elite goalie can be on the ice for 80% of the time a team plays (ignoring the games the backup goalie is in obviously).  I expect Montreal and NYR to have an above average PDO every year because they have the two best goalies in the world in their respective nets and that certainly adds up over time. I think it’s fair to expect both of them at around 101.5 PDO without calling them lucky.

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That said, the teams to watch out for are the Colorado’s and Calgary’s and Toronto’s of the world that have run to the playoffs on it. Those teams tend to stick out a lot more though, and generally have a PDO much higher than 101.5 despite having worse goaltending.

A huge personal pet peeve of mine is that teams with elite goalies tend to want to lock it down and win 1-0. I find that asinine. You have a massive advantage in net, there’s a lot of luck involved in most goals scored in the NHL, so your best bet is to play in a game with lots of goals. I’d much rather trade breakaways with a team if I had Carey Price in net as opposed to Brian Elliott.

JON: The Oilers’ 5-on-5 PDO is currently 101.0 (all situations), eighth highest in the league. Do you think the Oilers’ record so far has been “full value” or have they been getting a bit lucky?

BRIAN: Headed into the game against Chicago, the Oilers were tied for first in the Pacific Division and have been full value for it by the percentages. I think they got a bit lucky early, a bit unlucky in the second 10 set of games, but they are who they are: an average team in a bad division. I think it’s very fair to expect the playoffs if they can stay relatively healthy, and San Jose is the only team in the division that is clearly better than them.

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Once again, we thank Brian for being kind enough to answer these questions. He’s a good follow on Twitter, even if he is a Baltimore Ravens fan. (Go, Patriots!)

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