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1st and 2nd Assist Bias

Our friend Rich Pollock from Illegal Curve asked an interesting question: what kind of bias do we see in assist totals? I'd been thinking about this since the Sharks' October 17 game against the Ducks. Anaheim shot the puck into their own net and the official scorer gave the goal to a Sharks player unassisted...A few minutes later, they announced that an assist had been awarded on the goal...And then between periods, a second assist was added. We know the NHL doesn't pay too much attention to anything other than whether the puck went in the net, but gratuitously awarding assists seems ridiculous.

At any rate, there is a difference in how assists are awarded to the home and away team:

Home Home Away Away
A1 A2 A1 A2
All 94.6 79.7 93.6 76.7
EV 93.9 76.2 93.3 73.6
PP 98.6 93.4 97.7 91.3
SH 76.3 38.4 71.4 31.1

The first assist isn't substantially different, but the bias comes, not surprisingly, in the second assist. At the rink level, there's strong correlation between both home and away 1st and 2nd assist rates (ie - if a rink awards its own players a lot of first assists, they'll also get a lot of 2nd assists) but there's not much correlation between home and road team assist rates.

The three most-generous and stingiest rinks for home and away assists at even-strength are:

Hm Hm Aw Aw
col 96.0 nj 80.8 col 97.3 col 82.6
pit 95.6 stl 80.8 pit 96.2 pit 80.9
edm 95.5 col 80.7 cgy 96.1 cgy 77.5
was 92.0 atl 72.3 tb 91.1 atl 69.8
mon 91.4 was 69.1 la 90.9 buf 69.8
phi 91.0 mon 66.8 mon 90.7 ott 65.3

Pittsburgh and Colorado clearly seem to be the best places to play for assists on the road, and they're among the five rinks that are more likely to award an assist to the road team (Calgary, Washington and Anaheim are the others.) On the PP, most goals get a first assist - New Jersey, Pittsburgh, St. Louis and Tampa have awarded assists on 100% of their home team's PP goals since the lockout, and half the league has missed fewer than three assists.

For a random player, these differences don't mean a whole lot, but the scorer's favorite might pick up more than a handful of extra assists in Colorado.