Theres a ton of guy changing shifts all game, yet they’ve got it down to the second. Does each guy carry an electronic tag that registers everytime they enter and leave the bench? Doubt it. More likely its a bunch of guys with stopwatches.
In the same vein, how does Yahoo keep track of all its NHL games (or all its sports games in fact)? Each game has play by play, stats etc. Do people get paid to do this? Sounds like a great job.
It’s just someone’s job to keep track of it every line change. If it’s tricky enough, maybe that’s their only job – pro sports tends to generate a lot of little jobs like that. You can pay $100 a game to a local coach or just someone who knows hockey, and everyone will be happy.
Then, as long as you keep track of which five guys are on the ice at every moment of the game, you can calculate each player’s time on ice.
Echoing SmackFu, if you go to an NBA or NHL game, you will see a squadron of stat keepers. Usually each person has just one stat s/he is repsonsible for. It’s a lot easier that way. I’ve covered high school games for a local paper and on your own at a basketball game, it’s pretty hard to keep track of anything other than points, fouls, and free throw attempts. Even field goal attempts are hard to keep track of. Rebounds are surprisingly hard.
Whenever you see a delay in one of those websites updating, it’s usually because there is some unusual play that they are trying to sort out.
In hockey, they may be going off of TV monitor as well.
I have done this, working as a scorer for a stat provider at MLB,NFL,NHL, and NBA games. BobT is right about the fast pace being tough, especially for basketball, but its really not that big of a challennge for hockey. Players come onto the ice in shifts, and so when there is a shift change, I first note the time and then look to see which line is in the game. We’re talking about three players at a time, and they usually play in the same grouping. Only takes a few seconds to confirm which three players came in. They usually dont change shifts when a shot on goal is imminent, so ther are a few seconds of lull in the action anyway. And if you dont see who came in immediately, you can keep looking until you figure it out, while the play continues.
The hardest thing in hockey is seeing who scored a goal and who should be awarded an assist, but fortunately there is an official scorer to make that determination. We just report what he/she says.
The biggest challenge for a scorer is to always be paying attention, lest you miss something. Complex plays are the most challenging because events unfold more quickly than you can record them. Shift changes are relatively easy.