Quite frequently in talk about lines of a hockey team, you’ll find talk about how a certain team should be matching up certain lines against certain opponents. For example, a recent comment to me on twitter stated roughly that: “As long as the Isles match-up the Frans Nielsen line with the Canes’ Eric Staal line, they’ll be in great shape” – as the Canes basically only had one quality line (the Staal line) at the time of that comment. But as I replied on twitter, that isn’t quite right:

Competition, on a possession level, is pretty much a zero sum game in hockey.

What this means is this: If you have four lines, with the following true talents:

1. Line A: 53% Corsi

2. Line B: 51% Corsi

3. Line C: 49% Corsi

4. Line D: 47% Corsi

If you could match up any of these lines with an opponent’s top line, which would you match up? The answer is that it doesn’t matter, at least on a possession level. If you match up Line D with the opponents Line 1, then Line D will probably get crushed…..but Lines A through C will do better as a result. Why? Because if your worst line is facing the opponents’ best line, your best line is facing the opponents’ weaker lines! Even if some lines are better at shutting down opponent shots (a defensive specialist line) while others are better at getting their own (an offensive specialist line), this remains the case – remember, the best defense being a good offense is totally true in hockey – they can’t score from their own zone (usually).

On a possession level, competition is thus a zero-sum game. That doesn’t mean it totally doesn’t matter – what it therefore can do is change the pace of a game. If two teams match power vs power, you’re likely going to have a lower scoring game, as each line tends to cancel out each other’s advantages. By contrast, if two teams put their 4th lines against opposing top lines (This was the case for the Penguins and Isles in their playoff series two years ago), you’re going to wind up with a high scoring back and forth affair, as teams trade off having huge advantages in terms of the players on ice. At the beginning of the game, pace doesn’t matter, but as the game goes on, and one team has a lead, it makes logical sense to match lines, if possible, for the leading team to slow down the game and lower the pace of scoring, for the same reason that teams go into a defensive shell.

It should be noted that teams show VERY LIMITED ability to match lines throughout a game and particularly over a season, which is why competition barely moves the needle for individual players long term. So the above doesn’t matter anywhere near as much as even the above makes it sound.

If you’re a good reader, you’ll notice I’ve up till now kept mentioning the words “on a possession level.” This is because what I said isn’t totally true. Let’s go back to our Team again and add some information:

1. Line A: 53% Corsi, 10% individual shooting % (not counting D-Men shooting)

2. Line B: 51% Corsi, 9% Shooting %

3. Line C: 49% Corsi, 7% Shooting %

4. Line D: 47% Corsi, 7% Shooting %

Now our decision does matter to an extent. If we put power vs power, we’re sacrificing opportunities for our best scorers even if our possession ability is unchanged. If we put our fourth line against opposing top lines, we don’t lose that ability. Note that in this case, our situation is unchanged regardless of whether 3rd or 4th lines take top competition. This is probably why so many coaches put 4th lines out against top opponents – why waste your best shooters in situations where they’re more likely to be in the Defensive zone!

The thing is, even this doesn’t matter as much as it might sound, because the same is true for the other team as well, and again we’re getting back to a zero sum game – As Garret has pointed out, most teams have shooting % go down as you go further down the lines just the same as possession, so again, line matching simply becomes a matter of pace, rather than actually optimizing team results.

The same can also be said of zone-start matching: starting your fourth line in the O zone more often will minimize damage, but reduce scoring, and thus lower the pace, while starting the top line there will increase scoring, but increase your own damage. That said, it’s more likely for there to be offensive or defensive zone specialists – people better in one zone than another – than competition specialists (people particularly better against top competition than bottom comp?), so it’s not quite as zero sum as competition.

The only way this changes is if you have two lines equally good at possession but different in shooting talent– in that case you’d rather the worse shooting line take top competition, since it doesn’t matter on a defensive level, and this’ll gives your better shooters more offensive time. But on average across teams, this doesn’t happen that often (although it’s yet another good reason why fourth lines should be filled more with skilled players who simply can’t shoot – see Eric Tangradi – instead of grinders who can’t skate). So team competition matching doesn’t matter much.

In short, line matching is for the most part a zero-sum game. Don’t get too obsessed with it.