curling strategy
It’s hard to defend curling as a sport, but it sure is an interesting game. And one of my favorite parts of these Olympics.
I’m not alone. Wired:
Like many geeks who have come before me, I’ve become absolutely mesmerized by curling, and I haven’t even made it to the venue. But watching the matches on TV, I’m fascinated by the blend of precision and strategy that the game offers. What is it about sliding big granite rocks that can be so compelling?
Part of it is the endlessly morphing nature of the game’s strategy. I’m a big baseball-statistics guy, and I realized this morning that there are a couple of strong parallels between the two sports. Let me explain.
One of the revolutions in thinking about baseball in the past decade is the concept of expected runs. By analyzing the reams of play-by-play data available, you can determine how many runs you should expect to score in any situation in the game. So, for instance, if you have a runner on first and nobody out, you’d expect to score 0.953 runs that inning.
Now, obviously, you can’t score exactly 0.953 runs. But expected runs let you evaluate strategic decisions like stealing a base and bunting, to figure out if they’re good plays.
OK, now back to curling.
One of the key strategic elements in curling is which team has the hammer — the curling term for the last rock in an end. It’s obviously an advantage, but how much? And how important is it? Again, math to the rescue. My new favorite website, Curl With Math, has collected data on years’ worth of elite curling matches and broken down the winning percentage of teams in all sorts of score situations.
A curling game has 10 ends (like innings, a complete set of stones for each team). At the start of the game, with a tie score, the team with the hammer has about a 60 percent chance to win the game — that is, the hammer gives them about a 10 percent edge. Significant, but not huge.
It’s more interesting to look at decisions during the game. Often, teams with the hammer will chose to blank an end, knocking out the rocks so that no one scores, and so they can keep the hammer. That is, they choose keeping the hammer over scoring 1 point. Does that make sense?

