Why The Second Period is the Highest Scoring Period in Hockey

The second period of hockey has consistently been the highest scoring period on average. Since the 1989-1990 NHL regular season, only 10 seasons out of 35 (28.6%) has the second period not been the highest scoring period, and that is due to the fact that the third period has an advantage of the goalie pull, and subsequent empty net, inflating the amount of goals scored.

To give a more definitive picture by removing the empty net confounder, the second period has had more goals scored in all 35 seasons compared to the first period.

This can be easily explained by the “long change” dynamic of the second period. In the first and third periods, teams’ benches are closest to their respective defensive zones, making line changes easier due to the ability to more easily dump the puck into the offensive zone, and requiring less time to get off the ice. However, in the second period, teams switch sides, but they do not switch benches, leading to the “long change” dynamic, where teams’ benches are now closer to the offensive zone and further from the defensive zone. This creates both a positive effect for creating offense and a negative effect on defence, resulting in more goals being scored in the long run.

There are a couple specific reasons as to why having the benches slightly further from the defensive zone has such a noticeable impact on goal scoring compared to the first period. Firstly, having the bench closer to the offensive zone makes line changes much easier for teams that are currently applying offensive pressure. For example, if a team sustains pressure in the offensive zone for over one minute, the team in the offensive zone can more easily replace fatigued players with fresh players to continue pressuring and creating scoring chances. Simultaneously, the defensive zone players will become more fatigued and be unable to change due to the longer journey to the bench.

Secondly, regular line changes become more difficult with the long change and may lead to fatigued players, which in turn leads to slower players, or even players who are more likely to make a mistake. Difficulty changing also results in “bad line changes” more often, where a bad line change typically refers to a player, or multiple players, changing at inopportune times that lead to odd-man rushes for the opposing team. It is more difficult to change when the bench is further from the defensive zone, since a common strategy to change tired players is to dump the puck into the offensive zone so that the time it takes for the opposing team to retrieve the puck is enough time to make a line change. However, in the second period, this is not always the case, and sometimes, defencemen especially, do not have time to change, even after an offensive zone dump in. This is what leads to either longer shifts, and therefore fatigue, or riskier line changes, where defencemen may misjudge how much time they have, resulting in an odd-man rush.

In the post-season, these trends do not appear to be much different. As seen by the below graph, the 2nd period is generally a higher scoring period than the first, with only a few outlier seasons where the first period was higher scoring.

However, this is likely due to the smaller sample size of games in the post-season compared to the regular season, as the expectations in the long run would be that the second period would always have more goals than the first period.

Some characteristics that do sway post-season numbers slightly when compared to the regular season is largely related to third periods. In the playoffs, third periods have one characteristic that provides a goal advantage, and one characteristic that prevents more goals from occurring.

The goal advantage that third periods have come in the form of the goalie pull, but even more so than compared with pulling the goalie in the regular season. In the playoffs, coaches are even less shy about pulling the goalie for an extra attacker when a game may seem out of reach, as in the post-season there is nothing to lose when a team is on the brink of losing a game, or even worse, elimination. For example, in game 4 between the Tampa Bay Lightning and Columbus Blue Jackets in 2019, Lightning head coach John Cooper pulled the goalie for the extra attacker while down 4-3 in the game and on the brink of a 4-0 series elimination. After the Blue Jackets scored on the empty net to make it 5-3, Cooper kept the goalie pulled again, and even again after the Jackets made it 6-3, for a final score of 7-3 with three empty net goals allowed. Similarly, in the 2019 Stanley Cup Finals, while the Panthers were down 3-1 in the series and 7-3 in game 5, head coach Paul Maurice pulled their goalie late in the game despite fractional odds of a comeback, as the only other option was to not try at all and get eliminated. Contrarily, in the regular season, coaches would not risk such a low probability for a comeback and allow meaningless goals against, as this could be potentially harmful at the end of the season if it impacts the tie-breaker procedure. As a result, third periods in the post-season receive an extra advantage with the high rate of goalie pulls.

The second major difference between regular season hockey and playoff hockey that impacts period characteristics, especially the second and third periods, is the prevent defence strategy. To put it simply, prevent defence is a style of play more commonly seen in the playoffs, where teams protect a lead by dumping the puck out of the defensive zone or neutral zone to take time off the clock, and by conservatively having four players back and only one forechecker in the offensive zone. Although the chances of gaining puck possession in the offensive zone are low, having four players in the neutral zone and defensive zone prevents odd man rushes. When teams use this strategy, the goal is not for them to score more goals to build upon the lead, but rather to protect their own lead with extremely conservative defensive measures. Whether this strategy is optimal or not is up for debate, as teams using this strategy typically achieve very few shots on goal themselves, and one defensive mistake can completely change the game. However, this defensive style implies that scoring will be low for both the team defending and the team trying to overcome their deficit. The reason why this strategy is typically more common in the playoffs is because shot blocking naturally becomes more prominent, which isn’t necessarily sustainable over a tight 82 game schedule. Additionally, teams do not need to play as conservatively on an 82 game schedule, whereas each game is exponentially more important in the post-season.

As analyzed, it is no coincidence that the second period is generally the highest scoring period due to the “long change” dynamic. Some seasons we see third periods having more goals on average, and this has become the recent norm, as explained in this Slapshot Bets article: “The Rise in Empty Net Goals”. The post-season follows similar trends, however, the more extreme goalie pulling dynamics, as well as the more conservative defence results in volatile third period expectations, where some post-seasons third periods have the most goals, and others the fewest. However, in the post-season, second periods are generally still higher scoring than first periods, proving many of the same characteristics in the regular season to be present in the playoffs.