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Leafs Looking Up: Hockey Prospectus 2012-13 Review

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This year's Hockey Prospectus Publication indicates the Leafs 2012-13 edition may finally make the playoffs after wandering for 8 years in the wilderness.

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Reading Up Before The Season Starts Is a Good Idea
Reading Up Before The Season Starts Is a Good Idea
Tom Dulat

A few months ago - well prior to the ending of the NHL lockout - I was contacted by Ryan Wagman of the Hockey Prospectus writing team about reviewing their 2012-13 edition upon it's release. Ryan and I have had many friendly discussions and debates about the Leafs over the past few years so I was more than happy to take the opportunity to provide Leafs fans - particularly the readers here at PPP - with a glimpse inside what amounts to the most comprehensive advanced stats publication in the hockey world right now.

For starters, Hockey Prospectus has been working pretty consistently to add a new statistic or provide new information and analysis year to year. In the 2011-12 edition they added the metric described as the Core Age of NHL Teams which was developed by managing edtior Timmo Seppa. Subsequently, in 2012-13 they've added player usage charts which were originally developed by Rob Vollman of to describe a player's usage based on offensive zone start percentage, competition level faced, and the results they provided based on Corsi.

The Core Age rankings are provided for the past 4 years for all 30 NHL franchises, and the statistic is described as follows:

"Core Age is simply the sum of each skater's age times his value in Goals Versus Threshold divided by the sum of the GVTs on the team."

"It is a weighted average for each team - the age of its core players - that tosses out all of the strategically meaningless replacement-level players and counts each skater more, the better he is."

- Timo Seppa, Hockey Prospectus 2012-13

Toronto saw its Core Age decline from 2008-09 through the 2010-11 seasons. Then during 2011-12 it rose again for the first time in a while from 27th to 25th in the league. This was likely due to the drastically increased GVT contributions of a 28 year old Joffrey Lupul, the continuing production of a 28 year old Grabovski, and the off-season additions of David Steckel (29), Tim Connolly (30), Matt Lombardi (29), and John-Michael Liles (31), all of whom were given a regular skating opportunity with a team that seemed reluctant to allow its kids to step into larger roles. Interestingly, analysis is also ventured by Seppa on plots comparing team Core Age vs. skater GVT over the same stretch of time:

"... our next step is to look at each team's Core Age compared to the GVT of their skaters. Together the two metrics help tell us which way they are likely going from that starting point.*"

"*As an intelligent reader, you additionally need to consider a team's goaltending and the strength of their farm system to further zero in on what their future portends."

- Timo Seppa, Hockey Prospectus 2012-13

Suffice it to say that the review of Toronto's situation may surprise some - particularly when viewed through the lens of how the team played prior to the sad denouement at the end of last year.

Also included is a detailed description and summary of the work done by PPP frienemies Eric Tulsky and Geoff Detweiler over at Broad Street Hockey on The Importance of Puck Possession - largely focused on assessing the relationship between offense and zone entries. The description is succinct and includes many pretty graphs and charts, but the following by Tulsky says it best:

"Zone Entry data has generated a lot of excitement in the statistical analysis community. Most of our statistics focus broadly on what happened, whereas this provides an early foray into understanding why it happened."

- Eric Tulsky

While some of the information contained in Hockey Prospectus is available elsewhere online, such as GVT rankings for individual players and the aforementioned player usage charts, the key sections most useful to those looking for accurate projections of the season(s) to come are the VUKOTA projections for the individual players, and the listings of Corey Pronman's top 100 NHL prospects.

Tom Awad's GVT has been around for a number of years now and has also been catalogued for past seasons and retired players thus allowing for analysis and comparison across NHL generations. Following this foundational basis, VUKOTA seeks to assess probable outcomes for players in the upcoming NHL season based on their previous play and on the career trajectories of similar players in the past.

Pronman's listing of top 100 prospects updates his listing of the top 50 prospects provided in the 2010-11 edition of the Hockey Prospectus. The distinction between Pronman's scouting work and that done via other services is he focuses predominantly on puck possession skills that are closely correlated to team building success. He also weights his rankings heavily towards those players in positions that are more predictable - and thus can be stated with higher levels of certainty.

One of the outcomes of this type of assessment is that it closely aligns with perceptions of player value PRIOR to players making the NHL - i.e. those based on offensive contributions at lower tiers of the development ladder. Unfortunately this stems from a high level of uncertainty around the development of defensive and goaltending skill sets. We are still working on ways to track defensive ability and without an obvious measure or means to assess solid defenders and goalies early in their development there is little point in attempting to predict high value players well before they make the NHL.

In conclusion, I'd have to say that I'm generally in agreement with most of the analysis Ryan and the team at Hockey Prospectus provide on how the Leafs should fare this season. In the end though - predictions and probable outcomes are shots in the dark on the basis of what we know prior to puck drop. What we know right now is that the upcoming season is likely to be a wacky and wild race through a 48 game schedule.

The Leafs are slated to creep into the playoffs on the basis of maintaining their solid offensive output, even without any additions or changes in goal. But tracking the many potential developments of a team in disarray may prove a fool's errand this year, so we'll have to play the games to find out. While the predictions it contains may not hold up thanks to the volatility likely in a lockout shortened season, I strongly recommend obtaining a copy of the Hockey Prospectus 2012-13 edition to anyone with an interest in advanced hockey statistics. It's well written and provides a very comprehensive view of what you can expect from the various teams around the NHL this coming season. Digital downloads are available at the Hockey Prospectus website and hard copies can be obtained in order from Amazon.