The document analyzes the effects of changes to the NHL's overtime rules in 1999-2000. It finds that the new rules that awarded a point for losing in overtime and reduced the number of skaters increased the incentive for teams to play for overtime rather than a tie. This led to more overtime games and fewer ties as intended. Regression analysis found the new rules were associated with more third period shots, higher odds of overtime, and fewer games ending with no additional goals in the final minutes. The changes benefited fan incentives by making overtime more exciting and addressing demand for fewer ties.
1. Fit to be Tied: The Incentive Effects
of Overtime Rules in Professional
Hockey
By: Jason Abrevaya
Andrew Smith
Econ 340: Economics of Sports
2. Abstract
• This article analyzes the effects of a change in
incentive schemes implemented by the NHL.
• This “change” made by the League deals with
how points are given to teams in Overtime
games
3. Background
• The NHL is the major pro hockey league in
America and has 30 teams.
• The top 8 teams in each Conference make the
playoffs based on a ‘point system.’
• Old NHL point system, prior to 1999-2000:
– 0 points for a loss. (including overtime)
– 1 point for a tie.
– 2 points for a win.
• There is more incentive for a team to play for a
tie than risk a loss.
4. Background
• Prior to the 1999-2000 NHL regular season, an
abundance of games ended in ties.
• Ties do not occur in other sports leagues.
– MLB, NBA, NFL (rarely)
• American sports fans do not like ties.
• Quality of the NHL product was diminished by
teams playing conservative and defensive in
the 3rd period of games.
5. Background
• Starting with the 1999-2000 season, the NHL
made 2 rules changes regarding OT games:
1) A team that loses in overtime receives 1 point.
2) OT is played with 4 skaters (plus the goalie) per
team, rather than the 5 skaters used by each team
in regulation play.
Note: OT = Overtime
6. Questions
• How do the new OT rules of the NHL benefit
the incentives facing each team?
• How do the new OT rules of the NHL benefit
the incentives for fans?
• Will the new OT rules successfully address
consumer demand?
7. Methodology
• Data
– 1995-1996 season through 2001-2002 season.
– All 30 NHL teams.
– 7,821 regular season games.
• Regression Analysis
– Linear regression models and probit models are used
to predict the likelihood of a game reaching OT.
– 3 Sets of Games are considered.
• All Games
• Games Tied with 20 Minutes left.
• Games Tied with 10 Minutes left.
8. Variables
• Dependent Variables
– 3rd Period Shots-on-Goal Indicator
– OT Indicator
– No-additional-goal Indicator
• Independent Variables
– Old rules
– In division games
– Day / Game # of the season
– Average # of goals scored by the home team (Hgf)
– Average # of goals scored by the visiting team (Vgf)
– Average # of goals allowed by the home team (Hga)
– Average # of goals allowed by the visiting team (Vga)
– Difference in team quality (teamdiff)
9. Regression Results
All Games Games Tied with 20 Minutes Left Games Tied with 10 Minutes Left
3rd Period Overtime No Goals in 3rd Period Overtime No Goals in 3rd Period Overtime No Goals in
Shots-on- Last 20 Shots-on- Last 20 Shots-on- Last 10
Goal Minutes Goal Minutes Goal Minutes
Oldrule 0.3011** -0.0755** 0.4933**
Indivision 0.0715** 0.0942** 0.1842** 0.1572**
dayofseason
Hgf 0.6874** -0.1315** 0.8625**
Vgf 0.3956** 0.8704**
Hga 1.1272** -0.1608** 1.3921** -0.1588* -0.1995** 1.1681** -0.1932** -0.2027**
Vga 1.3329** -0.0843** -0.2206** 1.5830** -0.2097** -0.2771** 1.4402** -0.2368** -0.1422*
Teamdiff -0.2106** -0.1232**
* Significant at the 1% level.
** Significant at the 5% level.
10. NHL Results
Old OT Rules (1995-1996 New OT Rules (1999-2000
to 1998-1999) to 2001-2002)
Win 2 2
Tie 1 1
Loss (OT) O 1
Loss (non-OT) 0 0
Number of Games 4,251 3,570
% of Games going into OT 19.8% 22.2%
% of OT Games ending in a 71.1% 55.5%
Tie
Average OT shots-on-goal 3.76 4.54
in OT games
Average OT shots-on-goal 3.97 5.46
in games ending in a tie
11. Percentage of Games Going Into OT
(Table 4)
Old OT Rules New OT Rules Change P-Value
(1995-1996 to (1999-2000 to
1998-1999) 2001-2002)
Divisional 20.5% 24.7% +4.2% .0162
Non-Divisional 19.5% 21.4% +1.9% .0726
P-Value .4460 .0424
12. Conclusions
• The NHL achieves its goal of making OT more exciting
for fans and having fewer OT games end in ties.
– Percentage of OT games ending in a tie drops from 71.1%
to 55.5%.
• More OT games are played as a result of teams
receiving a point for getting to OT.
– Percentage of OT games occurring goes from 19.8% to
22.2%.
• Overall % of games ending in a tie drop from 14.1% to
12.3%.
• Incentives for teams and fans are satisfied.
13. Economic Theory
• How does this case apply to what we have
studied in class?
• Regression Analysis
– Relationship of variables based on observed data.
• P-values
• Team Incentives
• Fan Demands
14. Overtime Alternatives?
• In a 2002 poll, 75% of surveyed fans were pleased with
the new OT format.
• However, additional incentive for reaching OT could
have been removed.
• Alternative 1:
– 3 points for a regulation win.
– 2 points for an OT win.
– 1 point for an OT loss.
– 0 points for a regulation loss.
• Alternative 2:
– Leave the original OT system intact, with 4 on 4 play and a
10 minute period.
15. New Overtime Rule Changes
• Prior to the 2005-2006 season, the NHL
further changed OT rules.
– There were no more ties.
– A shootout system is implemented.
• NHL finally achieves its objective of making OT
exciting for fans.
