Calgary Flames

Using “required save percentage” to evaluate NHL teams

Goaltending is the most important position in the game. It doesn’t matter how good your centers are, how solid your defence is, any game can be saved or lost because of goaltending. Good goaltending can make up for a bad night up front, and at the same time, bad goaltending can completely sink a great game from the skaters.

The Calgary Flames know this probably more than most teams in the NHL. Plagued with mediocre goaltending for a long, long time, the issues in net haven’t gone away. Still, the Flames are wrapping up one of their best seasons in franchise history. The last time the Flames had this much regular season success was in 1989, the year they would go on to win their first Stanley Cup. That is impressive all on its own, but the Flames have risen to one of the top teams in the league with below average goaltending. They sit in 20th place with a .901 SV% on the year, slightly below the average of .904 league wide.

The Flames haven’t let poor goaltending hold them back from being near the top of the standings most of the season. Only two teams with save percentages below the Flames’ are currently in a playoff spot, and just one holds down a top three spot in their division (San Jose Sharks). Because of the Flames’ lethal offence this season, they haven’t needed stellar goaltending; the same story applies to the Sharks. On the flip side, there are teams like the New York Islanders, that are almost entirely in the playoff picture due to the incredible goaltending tandem of Robin Lehner and Thomas Greiss. Without them, the Islanders are probably on the outside looking in.

So, while goaltending has the ability to massively swing games in either direction game-to-game, the rest of a team’s performance does affect the level of goaltending required for each team to succeed. Looking into this “required goaltending” concept can give clarity on why teams are performing the way they are, give an idea of whether teams need better goaltending or not, and where a team’s biggest weakness is.

For the purposes of this assessment, required goaltending is synonymous with required save percentage, calculated by determining the minimum number of saves required on a per game basis for a team to register a win. This is done using the following formula:

For example, if a team wins a game by a 4-2 score while allowing 20 shots against, the minimum number of saves needed to register a win would be 17. This means the winning team is allowed to concede three goals, one more than the two it actually did allow. In this example, the actual save percentage for the winning team was 18/20 (.900), and the required save percentage was 17/20 (.850). For all games that resulted in a win, the required save percentage will be equal to, or lower than, the actual save percentage recorded. In losses, the required save percentage is higher than the actual save percentage.

Over a full season, this formula reduces to:

Right away, a few trends are expected. Teams with more wins than losses should have a higher actual save percentage than required save percentage, and the opposite for teams with more losses than wins. As well, teams that score more goals will have a lower required save percentage. Because a team’s average required save percentage is determined based on the level of goaltending required to win every game of the season, the league-wide average require save percentage should be much higher than the actual save percentage; even a 50 win team wins just ~60% of its games.

Looking league-wide, each team stacks up like this. For clarity, both charts below have been given the same bounds:

*Note: All status used in this analysis are up to and including each team’s 69th game.

The average required save percentage league wide is .935, significantly higher than the average actual save percentage in the league. The team with the lowest required save percentage is at .908 and the team with the highest is at .961.

The teams with the lowest required save percentage are the Sharks, Lightning, Flames, Maple Leafs, and Capitals. That is expected; scoring more goals generally results in winning more games. On the other side, teams that are at the bottom of the standings, like the Ducks, Kings, Senators, and Red Wings are among the teams with the highest required save percentage. These teams simply don’t score enough goals and allow so many shots that they can’t win games without excellent goaltending. However, joining these three basement dwellers are teams like the Stars, Coyotes, Canucks, Wild, and Canadiens, all teams that are still in the hunt for a playoff spot.

There is more to the story. The Predators, one of the best teams in the league, are the seventh lowest scoring team, yet have a required save percentage right around the average. The Hurricanes, the fourth highest scoring team in the league, has a required save percentage below average, yet are fighting for their playoff lives. Where things get interesting is when comparing actual and required save percentage.

For the chart above, a team that has has a required save percentage equal to their actual save percentage is operating at exactly their most ideal situation in terms of goaltending. Simply, they receive the goaltending they need to win games. As that disparity grows, it indicates that teams need higher quality goaltending than they receive to overcome their offensive output. The graph is sorted by actual team save percentage.

Looking at the far left of the chart, we see a mixed bag of teams. In the top 10 teams by actual save percentage, we see seven teams in top three division positions, one wild card team, and two teams outside of the playoff picture. On the other end of the chart, we see just one playoff team, accompanied by two teams fighting for a playoff spot and seven that are effectively out of playoff contention. Without good goaltending, it’s hard to do well in this league.

Looking at the required save percentages give some insight into why teams are doing the way they are. For example, the Islanders are almost completely buoyed by their goaltending. They have one of the highest required save percentages in the league (13th ranked) and get the best team goaltending in the NHL. If their goalies falter in the postseason, it doesn’t look like they have the firepower to make up for it. The Stars stand out on the left side of the chart as well. They have the second highest save percentage in the NHL, but have the third highest required save percentage. Ben Bishop has been a rock in the Stars’ crease, but it’s just not enough to make the team a playoff lock; their offence letting them down more often than not.

On the right side, the Sharks are the biggest outlier. Losers of five straight games, the Sharks look mortal for the first time in months. However, their team is so deep and scores so much that they’re having a great season despite poor goaltending from Martin Jones and Aaron Dell. They will not be a favourable team to match up against in the playoffs; with the lowest required save percentage, the Sharks will be very tough to beat if one of their goalies can be just around average in the postseason. They will likely score enough goals to cover up their goaltending woes.

At the end of the day though, the best team in the NHL is clearly the Tampa Bay Lightning. Not only do they score so much that they have the lowest required save percentage in the league, but they also have an all-world goalie tandem that has posted an average save percentage higher than their required save percentage. The Lightning are the only team to do this, and are the most complete team from almost every angle. They don’t need good goaltending, but get it anyway. They truly are a scary, scary opponent.

Winning games in the NHL starts from the net out. Without at least average goaltending, it is very difficult to be a perennial playoff team. Often, this is amplified in the playoffs, where a goaltender that gets hot at the right time can carry a team deep into the Spring. However, this season features a few teams that haven’t relied on goaltending en route to home ice advantage in the playoffs. Teams like the Sharks, Flames, Capitals, and Hurricanes aren’t among the best teams in terms of goaltending. Instead, they’ve used high powered offence to overcome struggles between the pipes.

Goaltending might be more important than any other position, but at the end of the day, hockey is a team game, and whichever team is able to put it all together between April and June will be rewarded with their names etched in the Stanley Cup. Buckle up, the 2019 playoffs will be fun.

Photo by Alex Gallardo/AP Photo

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