Switch to 3-on-3 overtime delivers scoring boost

One of the most exciting rule changes this season has been the transition from 4-on-4 overtime to 3-on-3. Not only have there been some dazzling displays of skill, but the majority of games have been decided before reaching the shootout portion of the tiebreaking process.

Though few knew exactly what to expect with the change, there was a general belief that scoring would rise and more games would be decided in the overtime period. The rate at which each has occurred is likely shocking to even the most ardent supporters of the switch.

In the Stanley Cup Playoffs, where tied games are sent to sudden-death overtime with five skaters per side, 35.4 percent of games are resolved within five minutes. Dating to the 2005-06 season, 73 of 206 games were decided in the first five minutes.

During the 2014-15 regular season, 136 of the 306 games extending past regulation were decided during 4-on-4 overtime, a rate of 44.4 percent. This season, the rate has vaulted to 70.6 percent, with 24 of the 34 tied games resolved in 3-on-3 overtime, as of Nov. 4.

The average time before a goal is scored has been 3:05, compared to 4:02 for overtime games at this point last season.

There wasn't a lot of data on which to base a projection of what would happen in 3-on-3 overtime because it is a unique circumstance, different from other 3-on-3 manpower situations arising in the course of the regular season. In the previous 10 seasons, there were 386.7 minutes of 3-on-3 play, during which 12 goals were scored (1.86 goals per 60 minutes). The number of shots increased significantly relative to 5-on-5 situations but 5.0 percent of those shots were successful.

This table breaks down the scoring in the various even-strength manpower situations, ranked by goals per 60 minutes. In order to get a full 82 games worth of data, the following information is from the 2014-15 season, with the obvious exception of 3-on-3 overtime.

Regardless of the manpower situation, overtime periods produce an increase in scoring because of a greater volume of shots and higher shooting percentages. With a point guaranteed to each team by virtue of reaching the tiebreaker, teams can shorten the bench and take some chances.

Removing a player from the ice, on the other hand, doesn't necessarily result in an increase in scoring. In regulation time, shots, shooting percentage and scoring go down when the situation changes from 5-on-5 to 4-on-4. That actually makes sense, because in 4-on-4 situations, coaches take a forward off the ice and defensemen then constitute 50 percent of the skaters on the ice, instead of a traditional 40 percent. Removing a second player, on the other hand, results in having twice as many forwards on the ice as defensemen.

Overtime scoring is also being boosted because the teams switch ends and play with a long change. That means a team has to control the play to make a line change. Failure to do so could result in fatigue-induced errors and quicker goals. That's one reason shots, shooting percentages and scoring, independent of the manpower situation, are up in the second period, which also has the long change.

Historically, 3-on-3 has been the lowest-scoring even-strength situation. There are far more shots but fewer go in. Last season, there were no goals during 3-on-3 play during the regular season. Three-on-3 situations are quite uncommon, generally do not last long and, by definition, follow multiple rules infractions by each team. Knowing the situation is temporary, it makes sense teams would opt to play defensive hockey. As stated, that thinking and the mindset that follows changes in overtime.

The shootout has proven to be an exciting, but otherwise random, skills competition with outcomes that have very little relationship to the relative abilities of the teams involved at playing hockey. Given their importance in determining which teams make the playoffs, and where they are seeded, it makes sense to strike the right balance in how many games are resolved this way.

The switch from 4-on-4 to 3-on-3 has proven to be an effective way to increase scoring and reduce the number of games that require the shootout to resolve. There wasn't enough data to accurately predict to what extent scoring would increase, but it's fair to say the results so far have exceeded expectations.