Puck Prospectus - Behind The Net: The Value of a Wide-Open Shot

September 25, 2009
Behind The Net
The Value of a Wide-Open Shot

by Gabriel Desjardins

The bulk of the analysis I’ve done on NHL shooting considers just the position of the shooter and sometimes the identity of the goaltender. This is not my optimal design, but it reflects what information is available in the NHL data feed. For three seasons, we’ve known which other players are on the ice, but we don’t know where they are. So we don’t know what impact defense or a screen had on a given shot on goal – a wrist shot from the face-off dot could be the end of a beautifully-executed give-and-go on a two-on-one, or it could be a weak lob on goal by a forward who’s being taken out by the defenseman.

However, there is one situation where only the shooter and the goaltender are involved: shootouts. The chart below shows where shots were taken from during shootouts over the last four seasons:

Obviously, when there are no opposing defenders, you end up with a lot of high percentage shots. Shooting percentages for shootouts are as follows:

Percentage	Goal	SOG	Save	Miss
Shootout	33.6	85.1	51.5	14.9

The 33% success rate is well-known – which is interesting, because typically shooting percentage has been expressed as a ratio of goals to shots on goal, excluding shots that miss the net.

At any rate, what we can now do is estimate the value of defense (and by extension, the positioning of all other players on the ice) by taking the locations of shots taken in shootouts and adding up the shooting percentages for those shots assuming they had been taken either at even-strength or on the power-play. In other words, if we had a team that took shots at the same locations as they were taken during shootouts, what would our team’s shooting percentage be relative to the 33.6% mark for an undefended shot?

As it turns out, quite a bit higher:

Pct	         Goal	 SOG	 Save	 Miss
During Play (ES) 12.8	 76.0	 63.3	 24.0
During Play (PP) 15.0	 73.1	 58.1	 26.9
During Play (SH) 13.6	 86.1	 72.4	 13.9
Shootout	 33.6	 85.1	 51.5	 14.9	 	 	 	 
Ratio (ES)	 2.63	 1.12	 0.81	 0.62
Ratio (PP)	 2.25	 1.16	 0.89	 0.55
Ratio (SH)	 2.47	 0.99	 0.71	 1.07

The impact of other players is, not surprisingly, quite substantial. Compared to even-strength play, shots are 2.63 times more likely to go in from these locations and 2.25 times more likely than on the power-play (which includes both one- and two-man-advantages.) Also not surprising is the significant drop in shots that miss the net (note that short-handed shots tend to come from defensive lapses and result in a lot of breakaways – hence fewer misses.) If we could somehow separate the impact of both teammates and opponents’ defense on scoring, it is likely that the defense would account for a three-fold drop in shooting percentage.

Gabriel Desjardins is an author of Puck Prospectus and runs the statistical hockey site behindthenet.ca. You can contact him at info at behindthenet.ca.