Thursday, May 17, 2007

Missed Shots

With the availability of NHL play-by-play records, many new statistics are being tracked. One such statistic is missed shots against a goaltender, which can be found at behindthenet.ca.

I have heard it argued that goalies who are solid positionally force shooters to miss the net more often. Anecdotally from my experience, this argument seems very reasonable, since goalies often can put themselves in blocking positions where they cover almost the entire net, making it very difficult for shooters to pick the corners. This, goes the argument, is one of the reasons why some goalies face fewer shots, such as Martin Brodeur. However, this position isn't supported by the facts.

According to Behind the Net, Brodeur ranked 45th in the league in the number of missed shots per 60 minutes at even-strength. He might have made a shooters miss a bit more often on the penalty kill, where he ranked 13th. But when his team was on the power play, he ranked 51st.

So Brodeur doesn't come off very well based on this metric. But are there some goalies who do routinely make shooters miss more shots?

Looking at some of the goalies who rated highly in terms of misses, there did not seem to be much correlation with talent. Among the goalies who made shooters miss often at both even-strength and on the penalty kill were Mathieu Garon, Dan Cloutier, Andrew Raycroft, and David Aebischer, four of the worst goalies in the league. At the other end, among goalies who rarely made shooters miss, could be found Nikolai Khabibulin, Chris Mason, Ilya Bryzgalov, and Tomas Vokoun.

The correlation between save percentage and miss rate was slightly negative, meaning that as save percentage went up, shooters were less likely to miss the net, not more likely, which goes against the conventional wisdom. One possible explanation for this is that good goalies are more likely to save shots that are going slightly wide or high, shots that then get recorded as saves whereas if the goalie had let them go they would be a missed shot on goal.

I then compared starting goalies to their backups to see if they forced more misses. Of all shots attempts at net that weren't blocked (i.e. saves, goals, and misses), 29.1% directed at the starting goalies ended up missing the net. The stat for backups was 28.9%, almost exactly the same. It was also similar on the penalty kill, 28.7% for starters, 27.7% for their backups.

I also looked at the correlation between starters and backups at even strength. It was .098, indicating almost no relationship at all. On the penalty kill, however, it was .268, indicating that team penalty kill tactics have a small influence on the rate of shots missed.

Missed shots therefore seem to be of little use in terms of evaluating goalies, at least based on this year's results. The missed shot rate does not seem to be correlated with goalie ability at all. If anything, shooters seem to miss the net less often against good goalies.

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