How important are faceoffs to possession in women’s hockey?


This was co-written by Mike Murphy, Alyssa Longmuir, and Shayna Goldman based on work for the Big Data Cup and Ottawa Hockey Analytics Conference
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As a result of women’s hockey analytics needing to play “catch up,” it’s not unusual to see analysts relying on stats that have already been proven to be less insightful in the men’s game. One such area of the game that is frequently highlighted at the collegiate, professional, and international levels of the women’s game are faceoffs. 

Faceoffs have been covered extensively in men’s hockey, and much of that work points to the fact that faceoffs wins aren’t all that they’re chalked up to be. Back in 2015, Arik Parnass, now of the Colorado Avalanche, found, “This … aligns with what hockey analysis has found over the years when it comes to faceoffs. Overall, winning them just isn’t as important as it’s made out to be.” 

While a great deal of work has been done on the importance (or lack thereof) of faceoffs in the men’s game the same cannot be said of women’s hockey. But why would it be any different? 

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Introducing NWHLe and Translation Factors

In April 2017, Rob Vollman tweeted out what he called “rough and preliminary” translation factors for women’s hockey. At the time, I was playing around with counting stats from two years of NWHL and CWHL hockey, and wanted to develop as many tools and resources as I could to better understand the women’s game. Curious to know what the competitive landscape of post-collegiate hockey looked like in North America and elsewhere, I began to keep track of data with the intention of building on Rob’s translation factors.

The world of women’s hockey in North America has changed dramatically in the three years since Rob’s tweet. My initial plans went up in smoke when the CWHL suddenly folded after the 2018-19 season. As a result, I shifted my focus to developing NWHL equivalency factors – or NWHLe – for NCAA DI, NCAA DIII, and USports. Unfortunately, it quickly became apparent that the sample size of USports alumnae to play a significant number of games in the NWHL was too small to work with.

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Revisiting NWHL Game Score

In March 2018, Shawn Ferris of Hockey Graphs introduced his NWHL Game Score, which was based on Dom Luszczyszyn’s NHL Game Score. It was groundbreaking work in women’s hockey analytics, which is still very much in its infancy — especially at the professional level.

Game score is a valuable tool that can give us a better understanding of a player’s performance than points for skaters or save percentage and goals against average for goaltenders. It provides us with a single value that incorporates relevant points of data which we can use to compare the performances of two or more players in a single game or over the course of many games, including seasons and careers.

As Shawn noted in his work, game score is particularly valuable for analyzing performance in the NWHL because of the brevity of the regular season. Through the league’s first four seasons, the average length of a season was under 18 games. The 2019-20 season promises a schedule of 24 games, which is still less than a third of the length of the NHL season. That brief schedule creates an opportunity for shooting percentage factors to influence both a players’ production and our perception of their performance.

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