If there’s one single factor that matters more than any other in hockey, it’s goaltending. A great goalie can carry a mediocre team to a Stanley Cup title, while a bad performance between the pipes can cost a team the game before the end of the first period. Goaltending is so important that no gambler should even think about betting on a hockey game without learning everything they can about the goalies involved.

It’s the biggest mistake any new hockey gambler can make. You see a line that looks too good to be true; one of the league’s top teams is at home, facing off against a middle-of-the-pack team, is an even money bet or a slight underdog. Knowing that they would normally be a big favorite, and that there are no serious injuries involved, you make a huge bet on the home team.

But when you sit down to watch the game, something is wrong. The home team is starting their backup goalie, one that has a goals against average (GAA) that’s nearly a full goal higher than the starter! Suddenly, that great bet looks like a disaster, and your only hope is to get lucky.

This example shows why it’s so important to keep an eye on who each team intends on starting in a given game. It’s not as obvious as in baseball, since the starting goaltender will play the majority of the team’s games, and they aren’t always listed in game previews like pitchers are. But a goalie can make as big a difference to a hockey team as a pitcher does in baseball, so knowing who will be minding the net is critical.

The most critical number to look at when judging how a goalie will impact a game is their GAA. This will tell you how many goals they allow in an average 60-minute game. This isn’t the only tool you’d use if you were trying to scout a goalie, of course. But in gambling, we’re not really concerned with how great the goaltender is on his own; we want to know how he and his defense work together to prevent goals, and GAA tells us that. If you want a little more insight onto how a recently traded or signed goalie might perform, save percentage can also come in handy.

However, we don’t want to simply consider a goalie’s overall numbers when thinking about how he’s likely to perform in tonight’s game. Goaltending can be very streaky, and a hot goalie can make any team into a juggernaut. Check out how a goaltender has done over the last few games; if their numbers have been outstanding, it may mean that they’re in good form and can be expected to continue putting up good results. Conversely, if you see their save percentages going down during recent games, and especially if that number goes below 90%, you can feel confident that a goalie is headed for a cold streak. It may be best to bet against that goalie when he’s playing, or at least refrain from betting on his team until he starts to come out of his funk.