Alright, I've been working on a game similar to WhatIfSports, and I was developing a set of formulas to determine defensive ability. After playing with the +/- stat, I had a hunch about the difference between the points a player scores and his +/-.
Conroy scored 47 points. His +/- was 13. The difference, then, is 34.
Now, I went through the game-by-game stats for Conroy on TSN, and counted up an approximate GA by looking for each game where his +/- was below his point total. Conroy's was 36.
Notice how similar his points/+/- difference is to the total I counted up.
I did this for Iginla, and the same thing happened- his points/+/- difference was 57, and the "GA" I determined was 52. I'm guessing the reason there's a slight variation is because of how the +/- stat works- namely, because shorthanded goals against for a player aren't tallied.
Oddly enough, this same phenomenon goes awry when it comes to defensemen:
Tarnstrom (52 points, -37)
Plus/Minus/Points Difference: 89
Niedermayer (54 points, +20)
Plus/Minus/Points Difference: 34
I don't think anyone really cares, but I just thought I'd point it out for all us stats buffs!
Mr Bugg, you might be interested in the Hockey Research.com site. Take a look at the Just the Stats section. The author explains his concepts like "Weighted Goals" and "Pythagorean Equation", one variant being based on +/-.
It's all a great read for us 'stats buffs', as you say. It was real neat when this first came out a few years ago, but unfortunately, the site hasn't been updated since.
Yeah, it's not so much the discrepency I'm interested in here... it's that they're so similar, and thus the difference you get by subtracting +/- from points is equal to an approximate GA for a skater.
Using game-by-game statistics, I counted up the number of goals that were scored against Calgary while Conroy was on the ice.
That number- his GA, or "Goals Against" for lack of a better term, was very close to the difference (think mathematically here- difference as in the result of two numbers being subtracted) that resulted from subtracting Conroy's +/- number from his total points.