August 4, 2006

Does the sniper exist?

When studying defense it didn’t take long to realize that defenseman are unable to make a statistically difficult shot easier or harder based on anything within their control; however the obvious question that follows: can a forward do anything beyond getting into the right position and taking a good shot? The obvious answer should be yes, players have different aim and skills. If a player can’t hit the net for the world of him then he is obviously doomed. I should note first, I am looking at plus ratings and as such I’m looking at all shots from all players while that person is on the ice. This is beneficial because it measures passing and shooting as well as position etc. Also it reduces the error as each player has about five times more shots given to them. The other question pertaining to shooters is their ability to get shots: who or what is responsible for shooting more?

The problem with snipers is choosing who is and who is not. The question of sniper comes from quality, and does not depend at all on quantity. So if we look whether a player has a better shooting percentage than expected then we have a sniper. Hockey analytics determined a shot quality neutral save percentage, the same can be said for shooter, and call it the shot quality neutral scoring percentage (SQN%) [1]. What this does is it compares the players shooting percentage to the league’s shooting percentage on the same shots. When you look at a list arranged by SQN%, you will see a lot of good players on top. The question is of error: what level of shooting percentage makes sense for what quantity of shots. How many snipers does each team have? How many snipers are there in the NHL? I’ll use 95% confidence rate. There are 120 players in this group, 50 of which are included due to error (you pick the 50…). This obviously isn’t perfect, but you can see this list, red indicates the opposite of snipers (statistically if snipers exist the anti-sniper most also, this list might be more interesting to some). When you think of the red: you should think of players who get chances, but don’t score. These players are frustrating to watch. The sniper seems to score with very few chances (or score a lot with a lot of chances), as with the plus statistic there is the problem of line mates, however you will notice that an entire line does not show up, often it is one key player (due to different lines periodically). Just because a player is not on this list does not make them bad or good necessarily, if they can get more shots on net then they are more valuable as well, or less shots would make them less useful.

So then the question of shots for comes into the mix. If you can’t score well with a few shots, why not shoot more. This strategy isn’t that bad, and considering that about 90% of players are in this group it would make sense to shoot a lot. However, can players control how much they shoot? Again the answer is yes, as the error is larger than expected. A similar list can be made for these players; however, players have more control over quantity than they do on quality. The 95% group contains 188 players, which is over 20% of all players, which is much better than the 12% in terms of shooting quality. This being said if you scale out the coaching (team) factor, the results appear very similar to shots in terms of distribution, you can see the list of players beyond 95%. The question of course where does the rest of the error come from then? The two lists (green and red), don’t contain the most skilled players necessarily. So a further analysis of shots: I compared each player to their team’s rate of shots for and against simultaneously. This basically means if you account for different coaching, teams will get the same net shots during a shift, meaning if a player was in the second red list they were playing poorly defensively and allowing a lot more chances in their own zone. The green players are better defensively. Another interesting conclusion one can make from this is that the best defense (preventing shots) is a good offense. This makes shots a measure of defense and as such one can measure offense purely on how well they do with the shots they get. Shot quality neutral shooting percentage. This doesn’t mean shots for don’t matter, and plus per minute is an excellent measure of a player; however this SQN% is an excellent way to see who are the best scorers. I’m not sure which players affect shots for and against (defense/forwards – defense determine which zone you spend your time in…?), but this certainly interesting insight into the game. A player with a good SQN% can make up for a poor offense due to the fact they can score more with fewer shots.

I have separated shots into to components: shots for, a measure of offense and defense, and a shot quality neutral shooting percentage, measuring a players ability to get a better than average shot off in a given location. So what if a player just gets in good positions and shoots average, this should be just as good. So one can look at just shooting percentage (which is already available), but this doesn’t always measure a players ability to score, or look at a lines shooting percentage with this list.

[1] SQN% - or shot quality neutral shooting percentage, is a measure of offense. It's calcualted by: (goals for/shots for)/(expected goals for/(league average shooting percentage*shots for)) or (goals for * league average shooting percentage/expected goals for). I don't expect this necessarily to make sense so you can go to Hockey Analytics and read about their Shot Quality article.

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