2009-2010 Shot Data From Around the League

John put together a great post postulating that the Devils newest shot blocking machine, Anton Volchenkov, might see his shot blocking numbers reduced simply by playing 41 games at the Rock. Peter Raaymakers from www.silversevensens.com queried

Obviously it would be a very difficult stat to compile, but I’d be interested to know how visiting teams are scored by the Rock’s scorekeepers, and how those numbers compare to their out-of-Jersey numbers.

If the game-by-game data on blocked shots is summarized somewhere, I didn't search too hard for it. But what I did find easily was that www.nhl.com includes game-by-game data that does include shots taken. So with a little repetitive copy/pastes into MS Excel and some formula manipulation. Well, more after the jump....

For quite some time Devils fans have suspected that the Devils official scorers are a little nit-picky when it comes to handing out shots. In our case, it seemed that sots on both ends of the ice are/were lower than the norm. In the NHL overall last season, home teams averaged 31.27 shots per game over 1230 total games played. The road team averaged 29.36. On the surface, I don't think there's too much question about home ice advantage and how that might translate to shots taken, so a difference of less than 2 shots per game sounds pretty reasonable. But when you break down the games based on team-by-team data, the differences are, well, let's just say cow pies in a pasture are more consistently placed.

I took the game-by-game summaries and added them up by team, both home and away, and averaged them by team. The numbers are quite surprising in some spots. As expected, the Devils are at or near the bottom of the league counting shots. There are a couple really interesting data points as well. But first, summarizing what exactly is contained in the table. The Team Diff H - A column indicates the difference between that team's average number of shots at home than on the road. A positive number means they average more shots at home than on the road. A small positive number wouldn't be surprising with the league average being 1.9. Opp Diff H - A indicates the difference between that teams' opponent's average number of shots at home and on the road.  Again, a positive difference meant that their opponents averaged more shots at home than their opponents averaged when they were on the road. One would think, based on the overall team average tending in favor of the home team, that the norm here would be a small negative number. I then ranked each of these differences. Well, here's the data:

As you can see, the Devils difference between shots taken at the Rock and when they are on the road is the highest in the league. Again, based on the overall average, one would expect to see any team's difference slightly positive, all things being equal. The fact that the Devils' number is the largest negative number in the league lends credence to the assumption that less shots are counted at the Rock than elsewhere. The Devils official scorers are just as cheap handing out shots to their opponents, being 29th worst in the league counting the Devils opponents shots at the Rock than are done when the Devils are on the road. At least they're consistently bad. I would speculate that since they err on the low side counting shots, they would do the same counting blocked shots.

One other data point that on the surface seemed surprising to me, but when I thought about it wasn't so surprising was the bias in Montreal. When Montreal is at home they average over 4 shots more than when they are on the road. This is over double the league average. Only in Colorado (and ties Mtl with Anaheim and Dallas) does the home team get a bigger benefit in shots counted. The surprising thing to me was that the Canadiens opponents average almost *7* fewer shots in Montreal than do Canadiens opponents when they are on the road. The next closest are the Devils, at almost 4. Again, the league overall averages slightly under 2. To put it in absolute numbers, where the home team averages 31.27 shots, Montreal would have 35. The visitor woutd average 29, but in Montreal, they'd only get credit for *22*. Similarly, in NJ, those 31 shots for the home team now average 29. The 29 shots the visitors take everywhere else comes out as 25 in NJ.

One would also think that those team's goalies save percentages would suffer for those teams with negative Team Diff H - A numbers. If the Devils scorers counted shots at the same rate as the league average, Marty would have had 93 more saves (assuming a 38/38 split between home/away games, I wasn't about to check, I'm sure it's close, it can't be off by more than 3 in either direction regardless). That would have raised his save percentage from .916 to just a hair under .920. All but one of the goalies with better save percentages than Martin Brodeur (Ilya Bryzgalov) had the benefit of a positive home bias. I'd say he'd have moved up from 13th to probably around 6th or 7th amongst the league leaders. Perhaps that will be the subject of another fan post.