Generally speaking, the fourth game in a best of seven series is a pretty big one.
Just look at the games tonight, where four series are at 2-1 and will swing to either 3-1 or 2-2 depending on the result.
Tomorrow, two more series are in the same situation.
Higher seeded teams up 2-1
Pittsburgh over Tampa Bay Washington over NY Rangers Philadelphia over Buffalo San Jose over Los Angeles
Lower seeded teams up 2-1
Nashville over Anaheim Montreal over Boston
Going from that 2-1 lead to either 3-1 (a virtual stranglehold on the series) or 2-2 (a deadlock) is obviously a dramatic difference. With help from whowins.com, here's a breakdown of what history tells us about teams in these situations:
When a higher seeded team has had a 2-1 lead, they have won the series 75.9 per cent of the time.
When a lower seeded has had a 2-1 lead, they have won it only 60.5 per cent of the time.
Increase that to 3-1, and the higher seeded teams have won 92.3 per cent of the series from that point on. Lower seeded teams have won 87.8 per cent of them.
Once the series goes to 2-2, however, it's basically a dead heat, with the higher seeded team having only a slight advantage historically due to playing two of the final three games at home.
A lot hinges on Game 4 in other words, and there'll be six of them in the next two nights.