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Advanced Team Stats - What the Heck is PDO?

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PDO is an advanced stat first introduced by and named for PDO, a frequent commenter in the Oilogosphere.  It was developed by Vic Ferrari at Irreverent Oiler Fans. PDO is a number you derive from added a team's even-strength shooting percentage to its even-strength save percentage. A more detailed analysis can be found here by MC79. For you mathematical junkies PDO = 1000 * (G/SF + SV/SA). Now inherent to PDO is that the average PDO for all 30 teams has to be exactly 1 because every shot either becomes a goal or a save.

PDO is great for analyzing is how well a team will do based on its overall scoring and goaltending. I've compiled PDO number for every team for the last 30 years using data from behindthenet.ca and put them in a Google Document for your enjoyment that can be found here.

Looking at this past season's numbers you can see why Washington was so dominant, shooting nearly 11% while 5-on-5 and somehow getting a fantastic .927 sv% out of their goalies giving them a PDO of 1.037, the highest PDO of the last three seasons. At the other end of the spectrum you have the Ottawa Senators who sported a league worst .895 sv% while 5-on-5; and that's even with that 11 game win streak where everyone pointed out that the goaltending wouldn't hold out. It didn't.

One of the most interesting facts I stumbled across while compiling this data was the fact that overall league shooting and save percentages at 5-on-5 have remained exactly the same over the last three seasons.  Team are scoring at a rate of 8.36% and thus goalies are stopping 91.64% of pucks thrown their way. While overall league scoring is up at even strength, this is due to an increase in the amount of shots being taken; 21.30 shots a game at 5-on-5 in 07-08, 22.32 a game in 08-09; 23.06 a game in 09-10.

Another thing I wanted to see was if there was a way to determing a team's ranking based on PDO. Turns out there is.  As you can see in the graphs below, for the last three years the formula relating end of the year rank to PDO remains virtually the same:

Pdovsrank20072008_medium

Pdovsrank20082009_medium

Pdovsrank20092010_medium

via img25.imageshack.us

Now obviously PDO is not the be all and end all for determining the strength of a a team. Just look at Chicago this year. They posted a 28th best PDO of 0.985 due to terrible goaltending. However, they led the league is shots against while only giving up 19.14 shots at 5-on-5. So even though their goalies stunk, thankfully for them they didn't see a lot of rubber.

How did Toronto fare?

Pretty bad. They posted a 28th ranked shooting percentage of 7.55% and the 26th ranked 5-on-5 goaltending with a 0.906 sv%. Not only does this team need to find a way to score more, they desperate need better goaltending. Now obviously Toskala shewed these numbers a bit, but even without his dismal numbers Leafs goaltending was subpar. From that MC79 post:

Toronto is an interesting team - they outshoot the opposition at evens by a healthy amount but have the worst PDO number in the league, thanks largely to their inability to stop the puck. Maybe Brian Burke’s first miracle, as certified by the Toronto press corps (I think we should call them "The Disciples"), will be to push their PDO number towards 100.

In conclusion

There is a lot more hidden information in the data I've collected than just what I've detailed here. So take some time to go through the numbers and discuss what you found in the comments below.