Back in 2013 I reviewed the initial edition of Rob Vollmans Hockey Abstract. I concluded that the book was a great jumping-off point for someone wanting to know more about hockey analytics, but might not be as interesting to the kind of person who was already frequently reading the likes of Eric Tulsky or Tyler Dellow.

My primary complaint about the book was that the organization was a bit confusing, as it seemed like Vollman might be trying to cover too much ground or appeal to too many different audiences. So how does the most recent edition fare?

Before I get to my verdict, let's back up a bit. You may be wondering what, exactly, Hockey Abstract is or why you should trust its author. Hockey Abstract is Rob Vollman's attempt to create something like Bill James's well known Baseball Abstract. It attempts to gather much of the current understanding of hockey analytics into one place, mixed in with a pretty hefty dose of Vollman's own work. The bulk of this year's edition is taken up with team-by-team breakdowns, but there's a lot of discussion of individual players, coaches, and ideas as well.

As for Rob, he's been writing about hockey statistics for years at a variety of outlets including Hockey Prospectus and ESPN, and he's recently begun writing an analytics column for If you're reading this article, odds are that you're familiar with his Player Usage Charts, which attempt to provide a quick snapshot of the deployment and results of the players on a team. He's also helped organise a number of analytics conferences, including one which I attended in Ottawa this past February that was a lot of fun. Rob's a respected voice in the analytics community, and just as importantly he's been around long enough to have a good grasp on the community's history. He's also a clear and capable writer, which is important in a field where math can easily overwhelm readability.

I would be remiss if I did not note that Tom Awad and Iain Fyffe both contributed to this year's edition, though the bulk of the writing is by Vollman himself. The book also draws heavily on the work of others, which is documented in the book's many footnotes. In fact, I would say that the degree to which Rob cites the work of others is one of the book's strengths. In addition to Rob's own writing, the 2015 edition of Hockey Abstract is a great resource for finding further reading material for anyone interested in the subject matter. I even noticed a few references to articles I didn't even know about by writers I try to regularly read! It's quite helpful to have a book that tracks so much of this material and brings it together.

Discussion about hockey statistics often seems to centre around Corsi and other puck possession metrics. One of the strengths of the first edition of Hockey Abstract was that it took a more holistic approach to stats, looking at the game from a bunch of angles. Vollman wisely continues that trend this year. While possession certainly makes its fair share of appearances, Vollman also looks at other elements of the game such as special teams, goaltending, and coaching. The book is certainly not 150 pages of "Corsi, amirite?"

In all likelihood, what you're here for is to find out if you should buy Hockey Abstract. The answer is "Yes" except when it's "No." I think my conclusion with the first edition mostly holds; if you're an avid reader of hockey stats writing, whether or not you should buy the book probably depends on just how voracious your appetite for this kind of material is. There probably isn't going to be too much that you don't know in the book, though it is well-written and, as I said above, if nothing else it does a great job of bringing a bunch of work (by Vollman and others) together in one place.

If you're looking to learn more about hockey stats, though, Hockey Abstract 2015 is a fantastic resource. It'll help you get up to speed on what kinds of issues and statistics hockey analysts are using. The book explains what kinds of factors we look for, why we value them, and how we use them.

Because the book focuses heavily on team-by-team breakdowns, it's organised in a yearbook-style structure that is easy to jump into. And while some hockey stats writing may seem to be an impenetrable wall of math and charts, Rob's written a book that's easy to understand without sacrificing the explanatory power of the underlying numbers.

If you're looking to buy a copy of Hockey Abstract 2015 Update, it's available as a PDF download for $10 from Rob's own site.

Physical copies of previous editions have been available, but this year's version is PDF-only. Rob has found a publishing partner for next year's edition, so it will be available in hard copy form once again at that point. I hope that in addition to the paperback, the publisher finds it worthwhile to publish an e-book edition. With its many links and charts, Hockey Abstract is a book that would be at home on your tablet, and the PDF version really doesn't have ideal formatting to work for that purpose, so hopefully an e-book will be forthcoming.