Are the Buffalo Sabres worse than an AHL team?

The Buffalo Sabres are not a good hockey team. This is not news to anyone. At 6-13-2 the Sabres sit last in the Atlantic Division by 6 points, and are tied with the Carolina Hurricanes and Edmonton Oilers for least points to date across the NHL. What’s worse for Buffalo is that they’re almost certainly much worse than their record suggests. Their Pythagorean Win Percentage, which calculates a team’s expected winning percentage based on their Goals For and Goals Against (and is a better predictor of future success than regular winning percentage) sits at 20.9%, 8% lower than their actual winning percentage.

It’s not easy to describe how bad Buffalo’s 20.9% Pythagorean winning percentage is: the only teams since 1992 to achieve anywhere close to that level of futility were the 1992-93 and 1993-94 Ottawa Sentors, and they at least had the excuse of playing in the first 2 years of their franchise history. One question that’s come up a few times across the sports analytics world recently is whether or not a minor league/college team could defeat the worst professional team in a given sport. Over at FiveThirtyEight, Neil Paine concluded that even the 0-14 Philadelphia 76ers would still be about a 78% favourite over the Kentucky Wildcats. In addition, Tom Tango ran through the math for MLB on his blog, and found that a top tier minor league team could score up to 70% as many runs while allowing 143% more and win up as even-money against the worst MLB team. The natural question that follows, of course, is are the Sabres really bad enough to lose to an AHL team?

To answer this, we’ll first need to figure out how well we’d expect the best AHL team to do (from a goal differential point of view) if we moved them up to the NHL. As of Tuesday night, the top team in the AHL was the Manchester Monarchs, who have posted 57 goals for and 38 goals against while en route to a 12-4-1 start. While the Monarchs have been slightly lucky to date (their Pythagorean Win Percentage is about 70% at that Goal Differential), their obviously still a good team. But because they play in the AHL we can’t just use the Goal Differential that they’ve posted there, we have to adjust it to reflect how we feel they’d perform if we airdropped them onto an NHL rink.

Fortunately for us, someone else has done the legwork to come up with a translation factor already! NHLe (NHL Equivalency) is a stat first created by Gabe Desjardins, and its purpose is to allow us to convert the number of points a player scored in a non-NHL league into NHL points. Based on Gabe’s work 1 goal in the AHL is worth approximately 0.45 in the NHL, meaning Manchester’s 57 AHL goals for are worth 25.65 in the NHL, and their 38 goals against translate to roughly 84.44 goals against. You don’t have to be a math major to see that a 25.65/84.44 GF/GA ratio is worse than 36/70, but how much worse is it?

If we look at Pythagorean Win Expectancy, the Monarchs NHL equivalent goal differential translates into roughly an 8.4% expected win percentage. We can compare that to Buffalo’s 20.9% expected win percentage by using an odds ratio method to come up with a neutral ice expected win percentage for both the Sabres and Monarchs:

Team Neutral Ice Expected Win %
Manchester Monarchs 25.9%
Buffalo Sabres 74.1%

Even the best AHL team will only win about 1 in 4 times against an historically bad NHL team, which really displays how big the difference in talent is between the NHL and AHL. While the Sabres may be in the middle of one of the worst non-expansion campaigns in recent memory, they’re nowhere near the level that we’d want to relegate them down to the American Hockey League.

One assumption we’ve made in our analysis, however, is that the NHLe is the same at the team level for goals for and against. While I feel fairly confident that it should work out for team goals for (you’re likely to have good players who will outperform it and bad players who will underperform), on the defensive side of the puck you could make an argument that our assumption won’t hold. By setting the NHLe for defense to 0.45 we’re essentially saying that we expect a team of AHLers to let up twice as many goals in the NHL as they did in the AHL. This doesn’t seem all that intuitive, as although we’d expect them to give up more shots and get slightly worse goaltending, general team defense should be easier to transfer between leagues than offense.

We can account for this by looking into how Manchester’s expected winning percentage varies as a function of the Goals Against NHLe.

Manchester Winning Percentage vs. GA NHLe

Manchester Winning Percentage vs. GA NHLe

In the graph above we see that the break-even point for our GA Equivalence multiplier is around 0.765, which is to say that if we believe that the Monarchs would give up 1.3 (1/0.765) times as many goals in the NHL as they would playing in the AHL, they’d be even money against the Sabres. While we don’t have a great way to test this, intuitively it doesn’t seem unreasonable, particularly if you consider the effect a strong goaltender could have. To date, the Monarchs have received 0.913 goaltending in all situations, if you were to drop that down to 0.905 and assume a 20% increase in shots against their goals against increases to 48, which is 1.28 times higher than their GA now. While we can’t say conclusively that this would be the case, it also doesn’t look like that unreasonable of a comparison to me. A 50/50 game may be the upper bound for the Monarchs, and while that may not be great for Manchester, it’s certainly worse for Buffalo.

While it does seem clear that the Sabres are at least not worse than the best AHL team, it’s still not exactly cause for celebration in Buffalo. Even in last place the Sabres are a bit lucky to be where they are in the standings given their goal differential, and while help may be coming up from Erie at the end of the season, the rest of this year is surely to be a long one for Sabres fans.

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Posted in Theoretical
5 comments on “Are the Buffalo Sabres worse than an AHL team?
  1. Ed Rodenburg says:

    Good post Matt. A lot of Oiler fans are already laying claim to McDavid in their annual “let`s talk about the draft“ in November routine.

    • Matt Cane says:

      It’s becoming a bit of a tradition isn’t it? I’m afraid that the Sens may end up in the same boat if they don’t turn things around soon, although they at least have a pair of goalies to rely on fortunately.

  2. […] What’s the one (non-tanking related) question fans around the league are asking about the Buffalo Sabres: Are they worse than an AHL team? (Puck++) […]

  3. Dude, if AHL goals are worth 0.45 NHL goals, Why is the Goals Against worth so much more than the Goals For? Explain your math to me. Shouldn’t it be a simple conversion? Because the Goals Against ARE AHL GOALS?

    • Matt Cane says:

      Sorry, perhaps that was a bit unclear. Gabe Desjardins calculated that a player scoring 10 points in the AHL would score about 4.5 points in the NHL on average (the 0.45 conversion factor). Converting goals for at this rate makes sense because we don’t really expect the team as a whole to differ too much from the average. The initial calculation (that showed the Monarchs at 25% vs. the Sabres) used this same factor, but in reverse. So each goal against in the AHL translates to roughly 2.22 (1/0.45) goals in the NHL.

      The issue with this approach is that the 0.45 conversion factor on defence is quite arbitrary. We don’t have any evidence to base our conversion factor off of, which is why I included the 2nd graph. The second graph shows what happens to the Monarchs expected winning percentage when we change the conversion factor. So when the conversion factor becomes about 0.765 for goals against (which means we need to multiply their goals against by 1.3) Manchester is roughly even with the Sabres. Looking back, it’s not really clear in what I’ve written that you need to divide the goals against by the conversion factor (after all, we expect goals against to go up when you move up a league).

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