The Win Threshold

I am firmly against comparing goalies based on wins. This is not because wins aren't important or desirable. Wins are what every player and team wants more than anything else. What makes wins a poor stat is that every team situation is different. If every goalie played the same schedule with identical teammates in front of them, then we could just give the Vezina to the guy with the most wins at the end of the season. In real life, goalies do not compete on a level playing field.

The two most important team factors that affect a goalie's ability to win are his goal support and the number of shots he has to face. More goal support means that more of his mistakes are covered up, and facing fewer shots against means fewer opportunities to allow goals.

Last year the Detroit Red Wings had the league's best offence, scoring 3.52 goals per game. They also allowed the second fewest shots against per game with 27.7. On the other end of the scale, the New York Islanders finished second last in both goals for (2.42) and shots against (33.5) per game. Quite obviously an Islander goalie would need to be much better than a Red Wing goalie for their teams to have the same chance at winning, because he would have to make up for his team scoring one less goal per game and he would have to do it while facing an extra half-dozen shots against.

We can calculate what I'll call the "win threshold" for the goalies on each team by taking (shots against - goals for) / shots against. This gives us the save percentage that would result in the team ending up with an equal number of goals for and goals against over the course of the season. If the goalie's save percentage is above that number, the team is likely to win more than the lose, while anything below the threshold means that the team should end up sub-.500 (or sub-.550 in the shootout era).

In 2008-09, Detroit's win threshold was .873, which was the lowest in the league. The Islanders' win threshold was .928, which was not only the highest mark in the league but also the highest of any team since the lockout.

Expressed a different way, Detroit is likely to win if their opponents have a shooting percentage of 12.6% or worse. The New York Islanders are likely to win only if their opponents have a shooting percentage of 7.1% or worse. The shooting percentage against Detroit needs to be almost 80% higher than the percentage against the Islanders for the teams to have the same likelihood of winning the game.

Naturally, comparing win totals on goalies playing on the Islanders to goalies playing on the Red Wings is completely senseless. It would be like comparing two students in terms of how many course credits they attained, where the first student passes their courses if they achieve a mark of 50% or better while the second student only passes if they score 90% or higher. With that advantage, the first student is much more likely to pass his courses and achieve a higher overall number of passes. Even if the second student is exceptional and the first student is mediocre, it is likely that the first student will have a similar or better score because of their inherent advantage.

I ran the formula for every team since the 1997-98 season, including an adjustment for average league goals and shots per game.

Top 10 since 1997-98:
1. 2001 Devils, .860
2. 2004 Senators, .866
3. 2000 Blues, .867
4. 2003 Senators, .868
5. 2008 Red Wings, .869
6. 1998 Blues, .872
6. 1999 Blues, .872
6. 1998 Stars, .872
6. 2006 Red Wings, .872
10. 2001 Avalanche, .874
10. 2003 Blues, .874
10. 2009 Red Wings, .874

Bottom 10 since 1997-98:
1. 1998 Lightning, .937
2. 2002 Thrashers, .935
2. 2000 Thrashers, .935
4. 2003 Panthers, .934
5. 2002 Blue Jackets, .933
6. 2002 Panthers, .932
7. 1999 Lightning, .931
7. 2000 Islanders,. 931
7. 2004 Panthers, .931
10. 2001 Wild, .930
10. 2004 Blue Jackets, .930

If you ever wondered how Roman Turek managed to get 42 wins in a season, or how Patrick Lalime won 39, here's your answer. On the other hand, note that four of Roberto Luongo's teams show up in the bottom 10. Why didn't the Florida Panthers make the playoffs? Because the team was terrible. It had nothing to do with the goaltending.

Note that these are team totals that need to be achieved, which make it even more difficult for goalies on the worst teams than it appears at first glance. If they have a backup who plays around 20-25 games at .900, then the starting goalie would need to be at .940 or better for the team to have a goal differential of zero. Even then, the team is unlikely to make the playoffs without scoring more goals than they allow.

The average win/loss record of the teams in the top 10 list was 48-22-12. The average win/loss record of the teams in the bottom 10 was 22-46-14. What is interesting, however, is that the goaltending performance was quite similar:

Save % of top 10 teams: .905
Save % of bottom 10 teams: .904

The teams on the top list didn't win because of great goaltending or because their goalie gave them clutch saves. They won because their teams scored a lot of goals and didn't allow many shots against. Similarly, the teams on the bottom list lost because they struggled to score and allowed too many shots against, not because their goaltenders were poor. This is further proof that win totals are a team stat, and should not be used to evaluate individual goalies.