National Hockey League Seasons Research Articles

Examining the Reliability and Validity of Coding Perceived Force Severity and Bracing in the NHL Concussion Spotter Program

Background: Data obtained from the National Hockey League (NHL) have shown that a risk prediction model, including both visible signs and mechanisms of injury, improves the identification of possible concussion. However, only about half of concussions diagnosed by club medical staff in the NHL exhibit visible signs. At present, the NHL concussion spotter protocol does not include central league spotters’ subjective judgments of the severity of forces associated with a direct hit to the head (perceived force severity [PFS]) or whether players brace before a hit (bracing). Purpose: To examine the interrater reliability, preliminary validity, and association with concussion diagnosis of central league spotter determinations of PFS and bracing. Study Design: Cross-sectional study. Methods: Video footage of 1071 events after a direct or indirect blow to the head were observed from the 2020-2021 and 2021-2022 NHL seasons. These events were classified into 4 groups: concussion with visible signs; concussion without visible signs; no concussion with visible signs; and no concussion without visible signs. A total of 50 events were randomly selected from the total events in each group. Then, 2 raters (NHL central league spotters) coded PFS for each of the 200 video events as low, medium, or high. Bracing was coded as no bracing, insufficient bracing, or full bracing. Results: Interrater reliability was fair to moderate for the categorical and continuous ratings of both PFS (κ = 0.36 and 0.45, respectively) and bracing (κ = 0.40 and 0.49, respectively). There was no significant association between concussion diagnosis and either PFS ( Z = 0.00, P = .99) or bracing ( Z = 0.77, P = .44). Exploratory, post hoc analyses suggested a possible relationship between bracing and reduced concussion risk among a select subsample of events with no visible signs ( r = −0.29, P < .01). Conclusion: The interrater reliability for PFS and for bracing was fair to moderate. Neither PFS nor bracing were significantly related to concussion diagnosis, but they were significantly associated with other visible signs and mechanisms of injury.

Concussions in ice hockey: mixed methods study including assessment of concussions on games missed and cap hit among National Hockey League players, systematic review, and concussion protocol analysis.

Concussions can occur at any level of ice hockey. Incidence estimates of concussions in ice hockey vary, and optimal prevention strategies and return-to-play (RTP) considerations have remained in evolution. The authors performed a mixed-methods study with the aim of elucidating the landscape of concussion in ice hockey and catalyzing initiatives to standardize preventative mechanisms and RTP considerations. The authors performed a five-part mixed-methods study that includes: 1) an analysis of the impact of concussions on games missed and income for National Hockey League (NHL) players using a publicly available database, 2) a systematic review of the incidence of concussion in ice hockey, 3) a systematic review of preventative strategies, 4) a systematic review of RTP, and 5) a policy review of documents from major governing bodies related to concussions in sports with a focus on ice hockey. The PubMed, Embase, and Scopus databases were used for the systematic reviews and focused on any level of hockey. In the NHL, 689 players had 1054 concussions from the 2000-2001 to 2022-2023 seasons. A concussion led to a mean of 13.77 ± 19.23 (range 1-82) games missed during the same season. After cap hit per game data became available in 2008-2009, players missed 10,024 games due to 668 concussions (mean 15.13 ± 3.81 per concussion, range 8.81-22.60 per concussion), with a cap hit per game missed of $35,880.85 ± $25,010.48 (range $5792.68-$134,146.30). The total cap hit of all missed games was $385,960,790.00, equating to $577,635.91 per concussion and $25,724,052.70 per NHL season. On systematic review, the incidence of concussions was 0.54-1.18 per 1000 athlete-exposures. Prevention mechanisms involved education, behavioral and cognitive interventions, protective equipment, biomechanical studies, and policy/rule changes. Rules prohibiting body checking in youth players were most effective. Determination of RTP was variable. Concussion protocols from both North American governing bodies and two leagues mandated that a player suspected of having a concussion be removed from play and undergo a six-step RTP strategy. The 6th International Conference on Concussion in Sport recommended the use of mouthguards for children and adolescents and disallowing body checking for all children and most levels of adolescents. Concussions in ice hockey lead to substantial missed time from play. The authors strongly encourage all hockey leagues to adopt and adhere to age-appropriate rules to limit hits to the head, increase compliance in wearing protective equipment, and utilize high-quality concussion protocols.

Concussion Characteristics in the National Hockey League Before and After the Introduction of Rule 48

A rule prohibiting a direct hit to the lateral side of the head (ie, Rule 48-Illegal Check to the Head) was introduced in the National Hockey League (NHL) in the 2010-2011 season and refined in the 2011-2012 season to widen the application to include direct contact to all areas of the head. To compare the incidence and proportion of concussions that occurred following hits to the head before and after the implementation of Rule 48. This retrospective cohort study used a before and after design to evaluate concussions among NHL players in regular season games. Data from the 4 seasons preceding the implementation of Rule 48 (2006-2007 to 2009-2010) were compared with data from 5 seasons following its implementation (2014-2015 to 2018-2019). Data were analyzed from October 31, 2021, to November 30, 2022. The incidence and relative proportion of concussion characteristics and mechanisms before and after the introduction of Rule 48. In the analysis of 688 concussions for NHL seasons spanning 2006 to 2010 (n = 231) and 2014 to 2019 (n = 457), there was an overall increase in the incidence of concussion between the 2 time frames, although the incidence of concussions due to hits to the lateral aspect of the head decreased from 1.6/100 games to 1.0/100 games (estimated difference, 0.6/100 games [90% credible interval (CrI), 0.30/100 games to 0.90/100 games). There was also a reduction of 18.8 (90% CrI, 13.0-23.7) percentage points in the proportion of concussions due to hits to the lateral aspect of the head from 80 of 231 concussions (34.6%) to 61 of 457 concussions (13.3%). The incidence of concussions following hits to the head from body checks using the shoulder, arm, and glove was similar before and following the implementation of Rule 48. However, the proportion was reduced 14.7 percentage points from 113 of 231 concussions (48.9%) before to 149 of 457 concussions (32.6%) after implementation of Rule 48 (90% CrI of the difference, 8.9-20.7 percentage points). The findings of this cohort study of NHL players suggest that after the introduction of Rule 48, the incidence rate and proportion of concussions from contact to the lateral aspect of the head decreased, as did the proportion of concussions following direct hits to the head.

Fighting in the National Hockey League: Before, During, and After the Pandemic

Fighting has long been a tradition in the National Hockey League (NHL). The impact of violence in the NHL on attendance has been widely studied. But, one could only surmise the counterfactual of how empty arenas influence player behavior, that is, until 2020. The COVID-19 pandemic forced NHL teams to severely limit attendance. The authors compare the proportion of regular season home games with at least one fight for each of the 31 NHL teams one season before, during, and one season after the 2020-21 NHL season. Did the absence of fans impact fighting? While there are few significant differences year to year (between 2019-20 and 2021-22), the incidence of fighting increased for most teams after fans were allowed back into arenas in 2021-22 compared to fighting one season before the COVID-19 NHL season without fans.

Relationship of Fitness Combine Results and National Hockey League Performance: A 25-Year Analysis.

Along with past performance, professional teams consider physical fitness and physiological potential in determining the value of prospective draft picks. The National Hockey League (NHL) Combine fitness results have been examined for their ability to predict draft order, but not bona fide hockey performance. Therefore, we sought to identify the relationships of combine fitness test results to short- and long-term NHL performance. During NHL Combine fitness testing (1994-2007), a standardized battery of tests was conducted. Player performance (1995-2020) was quantified using career cumulative points, time on ice, transitional period to playing in the NHL, and NHL career length. Forward and defensive positions were considered separately. Goalies were not considered. Stepwise linear regression analysis was used to identify fitness variables that predict NHL success. Overall models ranged in their predictive ability from 2% to 16%. The transitional period was predicted by peak leg power and aerobic capacity (V˙O2max; forwards, R2 = .03, and defense, R2 = .06, both P < .01). Points and time on ice within seasons 1 to 3 were predicted by peak leg power and V˙O2max for forwards and defense (R2 = .02-.09, P < .01). Among players accumulating 10 NHL seasons, cumulative points were inversely related to upper-body push-strength-related variables in forwards (R2 = .11) and defense (R2 = .16; both P < .01). The NHL Combine fitness testing offers meaningful data that can inform the likelihood of future success. Peak leg power and V˙O2max predict league entry and early career success. Counterintuitively, upper-body strength is inversely related to long-term performance, which may offer insight into recruitment strategies, player development, or differential team roles.

Winning and losing streaks in the National Hockey League: are teams experiencing momentum or are games a sequence of random events?

Abstract The Saint Louis Blues were hot at the end of the 2018–2019 National Hockey League season, winning eleven games in a row in January and February, and eight of their last ten. They parlayed this momentum to their first Stanley Cup Championship in franchise history. Or did they? Did the series of wins at the end of the season give the Blues the momentum needed to reach the pinnacle of the sport on June 12th, or was the Blues’ path to victory the confluence of a series of random events that fell in their favor? In this paper we apply entropy as an unbiased measure to further refute the idea of momentum in sports. We show that game outcomes are not dependent on previous games’ outcomes and conclude that the theory of momentum, across the season, is a fallacy that should not affect behavior.

Professional Sports and Crime: Do Professional Hockey Games Increase City-Level Crime Rates?

Previous research has found that sports games increase certain crimes including theft and vandalism, but the relationship between sports and other offenses such as motor vehicle theft, robbery, and assaults is mixed. Using regular season National Hockey League (NHL) game data and city-level, incident-level crime data from four large U.S. cities, this paper estimates if professional ice hockey games played at home is associated with increases in property crimes, alcohol-related crimes, and assaults during and right after games the over course of four NHL seasons. Results show that NHL games lead to small but significant increases in property crimes and assaults. There is no significant effect for alcohol-related crimes. Implications and suggestions for future work are discussed.

The Fractured Messaging of the National Collegiate Athletic Association and Its Members in Response to COVID-19

The sports world’s near universal moratorium in response to the COVID-19 pandemic was abrupt and unprecedented. From professional leagues to youth sports, doors were closed to competitions and events to help stop the spread of the coronavirus. The hiatus began at one of the busiest times on the calendar for sport, with the National Basketball Association and National Hockey League seasons concluding; the Women's National Basketball Association and National Football League drafts taking place; Major League Baseball's spring training nearing its conclusion; the Professional Golf Association and Ladies Professional Golf Association Tours starting their seasons; and the National Collegiate Athletic Association's marquee events, the Division-I men’s and women’s basketball tournaments, set to begin. The suddenness of the interruption was met with a need by the various sport entities to engage their public with information about their respective responses. The statements that emerged on or after March 12—“the day the sports world stopped”—were not all the same. Many of the statements, in fact, were quite different. That was especially the case with the National Collegiate Athletic Association, whose governance structure and messaging practices hindered their ability to have a uniform response. The purpose of this essay was to examine the public messaging of sport leagues and organizations and to discuss the effectiveness (or ineffectiveness) of those public statements.

Coping resources and strategies of Canadian ice-hockey players: An empirical National Hockey League career model

Sport psychology researchers have studied careers of Canadian ice hockey players in the National Hockey League (NHL) and devised an empirical NHL career model. The model was comprised of career stages, statuses, demands and barriers to career progression without any indication of coping. The intent in the present article is to feature coping resources and strategies utilized by players during each status and career stage within the empirical model. Five rookies, 5 veterans, and 13 retirees participated in conversational interviews and the data underwent a deductive thematic analysis. Prospects seeking to gain entry into the NHL set controllable expectations rather than playing to impress coaches and staff. Most prospects played in the minor leagues where they adjusted their expectations to accept roles that they were likely to have during an NHL call-up. The career stage of developing as an NHL player was about rookies producing immediately in their role while holding off internal competition for their roster spot. In the same stage, sophomores were in their second full NHL season and they studied their opponents to avoid the sophomore slump. The stage of reaching the NHL elite involved constant pressure for point production and winning playoff games. The final stage was about seasoned veterans maintaining NHL play involvement by preserving their physique despite being worn down from long careers in a contact sport. The authors will discuss the significance of the model for sport psychology researchers and practitioners, and NHL stakeholders.

Ocular and facial injuries sustained by goaltenders in the National Hockey League: a preventable problem

ObjectiveDespite mandatory helmets and face masks, professional and amateur goaltenders continue to be at risk for eye and facial injuries. Better understanding of the mechanism of injury would help in optimizing goaltender equipment. The goal of this study was to identify eye and orbital injuries to goaltenders in the National Hockey League (NHL) over the past 5 seasons. DesignRetrospective case series. ParticipantsAll NHL goaltenders from the 2014–2015 to 2018–2019 regular seasons. MethodsWeb-based sports injury web sites were searched to identify eye and facial injuries among goaltenders between the 2013–2014 and 2018–2019 NHL seasons. ResultsFive in-game eye, orbital, or facial injuries to NHL goaltenders were retrieved, resulting in an incidence of 4.07 per 10 000 athlete exposures. A total of 5 games were missed due to these injuries, resulting in a lost financial value of $335 937. All goaltenders in the NHL during the study period wore noncertified goaltender masks, and the mechanism of injury was the same in all cases, involving the blade of a player's stick accidentally passing through the gaps in the goaltender's facemask. All included players left the game in which they were injured, and the mean number of games missed was 1 (range 0–2). ConclusionsDespite mandatory facial protection, the use of noncertified masks is inadequate to prevent all facial and eye injuries. Serious consideration should be made to adapt new legislation in professional hockey.

The effects of altitude on concussion incidence in the 2013–2017 National Hockey League seasons

IntroductionAltitude cannot be adjusted yet can still impact quality of play and concussion incidence. The current body of published evidence evaluating environmental effects on concussion is divided. We aim to systematically compare the prevalence of concussions that occur utilizing 1,000 feet as a marker for high altitude. Our research also takes a novel approach utilizing average games missed as a proxy for concussion severity.MethodsData on concussion incidence for the 2013–2017 National Hockey League seasons was collected utilizing FOX Sports, Hockey Reference and elevation map. We adopted 1,000 feet (304.8 meters) as high-low altitude cutoff. We also evaluated our data utilizing a previously published high-low altitude cutoff of 644 feet. One caveat to our data collection was the striking lack of publicly available data pertaining to the concussions sustained by each NHL team. Data was analyzed utilizing SAS programing.ResultsWe documented 133 concussions through the 2013–2017 NHL seasons. We noted an increase in concussion reporting during the most recent 2016–2017 season compared to previous ones. Effect of altitude variance on concussion rate was evaluated utilizing 644 and 1000 ft as the altitude split. This produced 4 distinct categories: (1) low-low, (2) low-high, (3) high-low, and (4) high-high. We noted a significant difference in concussion rate when teams based at altitude above 1,000 ft played at low altitude. Average games missed demonstrated that teams above 1,000 feet experienced less games missed compared to low altitude teams.ConclusionsThough underreported in the total number of concussions, our data suggests that high altitude teams experience a reduction in mean concussion rate when playing at lower altitudes. Our data also indicated a reduction in average games missed post-concussion for higher altitude teams. We hope our findings contribute to a larger discussion about concussion incidence and can be applied to additional sports leagues.

Modifying Factors for Concussion Incidence and Severity in the 2013-2017 National Hockey League Seasons.

IntroductionIn the past few years, there has been a rising interest in both the prevalence and the short- and long-term consequences of concussions. While the main focus of concussion-based research revolves around the National Football League (NFL), attention is now shifting to other high contact leagues like the National Hockey League (NHL), where there is constant player-to-player contact as well as collisions with the perimeter boards. While the body of evidence surrounding injury and concussion rates in the NHL has substantially grown in size over the previous few years, there is still a void pertaining to the in-game effects that could modulate concussion incidence. Our study takes a novel approach to evaluate several “style of play” factors such as home/away perspective, win/loss outcome, points scored, real time length of game, time of season, and player position in modulating concussion rates.MethodsData on concussion incidence for the 2013-2017 National Hockey League seasons was collected utilizing FOX Sports injury tracker. Only injuries specifically diagnosed as concussions during regular and postseason games were utilized in our data set. A Google search on the reported injury was performed in order to correlate the concussion to the correct game in which the player sustained it. NHL season schedules were acquired through the online source “Hockey Reference.” There were a total of 5281 games when considering the regular and postseason games between the 2013-2017 seasons. Concussions sustained during team practices and preseason contests were not accounted for in our data set to control for inconsistent reporting. Our data set does not account for the current 2017-2018 NHL expansion with the addition of a Las Vegas team to the league.ResultsStatistical analysis of several "Style of Play" factors such as home/away perspective, win/loss outcome, points scored, real time length of game and time of season produced non-significant results pertaining to modulating concussion rate during the 2013-2017 NHL seasons. When evaluating on-ice position we noted offensive players combined to have the highest rate of concussion. Forwards (left wing (LW), right wing (RW)) demonstrated similar concussion rates, while goalies encountered the lowest concussion rate.ConclusionThe results of our analysis demonstrated non-significance for home/away effects, win/loss results, average points scored, real time length of game, and time of season on influencing concussion rates. We noted offensive players combined to have the highest rate of concussions, while goalies encountered the least. The key limitation in our data set is the lack of reliable and publicly available data surrounding concussion incidence in the National Hockey League. Due to this drawback, our data set should be considered as an under-reported representation of the total amount of concussions spanning the 2013-2017 seasons.

Short-Term Impact of Concussion in the NHL: An Analysis of Player Longevity, Performance, and Financial Loss.

Many studies have focused on the long-term impact of concussions in professional sports, but few have investigated short-term effects. This study examines concussion effects on individual players in the National Hockey League (NHL) by assessing career length, performance, and salary. Contracts, transactions, injury reports, and performance statistics from 2008-17 were obtained from the official NHL online publication. Players who sustained a concussion were compared with the 2008-17 non-concussed player pool. Career length was analyzed using Kaplan-Meier survival curves and stratification of player age, experience, and longevity. Player performance and salary changes were evaluated between the years before versus after concussion. Performance and salary changes were compared against non-concussed NHL athletes before/after their career midpoints. Of the 2194 eligible NHL players in the 9-year period, 309 sustained 399 concussions resulting in injury protocol. The probability of playing a full NHL season post-concussion was significantly decreased compared with the non-concussed pool (p < 0.05), specifically 65.0% versus 81.2% at 1 year into a player's career, 49.8% versus 67.4% at 2 years, and 14.6% versus 43.7% at 5 years. Performance was reduced at all non-goalie positions post-concussion (p < 0.05). Players scored 2.5 points/year less following a concussion. The total annualized financial impact from salary reductions after 1 concussion was $57.0 million, with a decrease of $292,000 per year in contract value per athlete. This retrospective study demonstrates that NHL concussions resulting in injury protocol activation lead to shorter career lengths, earnings reductions, and decreased performance when compared with non-concussed controls.

The Effects of Altitude on Concussion Incidence in the 2013-2017 National Hockey League Seasons.

Background and objectiveThe high incidence of traumatic brain injuries during contact sports has necessitated the need for further research pertaining to their implications and possible mitigation. Despite increasing attention to sports-related concussions, there is still a striking lack of detail pertaining to the environmental factors that contribute to their occurrence. One environmental condition that has yet to be considered is altitude. Altitude cannot be readily adjusted, yet can still impact quality of play and concussion incidence. The current body of published evidence evaluating environmental effects on concussion is divided on the degree to which altitude mitigates concussion incidence. We aim to systematically compare the prevalence of concussions that occur at high and low altitude utilizing 1000 feet (304.8 meters) as a cut-off marker for high altitude. Our research also takes a novel approach utilizing average games missed as a proxy for concussion severity. We hope to use this analysis to shed light on the implication of altitude on concussion incidence.MethodsIndividual player data on concussion incidence were retrospectively acquired for the 2013-2017 National Hockey League (NHL) seasons utilizing FOX Sports Injury tracker. NHL season schedules were acquired through the online source “Hockey Reference.” In order to establish cutoff criteria for high vs low altitude we adopted 1000 feet (304.8 meters) as high-low altitude cutoff. We also evaluated our data utilizing a previously published high-low altitude cutoff of 644 feet (196.3 meters). Specific altitudes of each NHL arena were derived from “elevationmap.net”. One caveat to our data collection was the striking lack of publicly available data pertaining to the concussions sustained by each NHL team. Data was analyzed utilizing SAS programing.ResultsOut of the 5281 games included in our data set, we documented a total of 133 concussions which occurred in 125 games through the 2013-2017 NHL seasons. We noted an increase in concussion reporting in the most recent 2016-2017 NHL season compared to the previous 2013-2016 seasons. Effect of altitude variance on concussion rate was evaluated utilizing 644 and 1000 ft as the low-high altitude split. We defined each variance by where the team is based at compared to where the game was played. This produced four distinct categories: 1) low-low altitude, 2) low-high altitude, 3) high-low altitude, and 4) high-high altitude. We noted a significant difference in concussion rate when teams based at high altitude above 1000 ft travel to play at low altitude; this trend was non-significant at 644 ft. The results of the average games missed analysis demonstrated that teams that play above 1000 feet had fewer games missed per concussion compared to teams that are based at a low altitude.ConclusionsThough underreported in the total number of concussions in the 2013-2017 NHL seasons, our data suggests that teams who are based at a high altitude (>1000ft) experience a reduction in mean concussion rate when traveling to play at a lower altitude. Our data also indicated a reduction in average games missed post-concussion for teams based at a higher altitude. It is our goal that our findings here contribute to the larger discussion about concussion incidence and can be applied to other sports leagues and activities to mitigate their dangerous effects.

Examining the home advantage in the National Hockey League: Comparisons among regulation, overtime, and the shootout

ObjectivesTo investigate the magnitude of the home advantage in the National Hockey League (NHL) as games proceeded from regulation, to overtime, to the shootout, while adjusting for team quality. DesignArchival. MethodBinary logistic regression analyses were conducted using data from the 2005–2006 through 2013–2014 NHL seasons (N = 10,534 games) to compare home teams’ odds of winning in regulation, overtime, and the shootout. ResultsCompared to games decided in regulation, higher quality home teams' odds of winning were slightly lower when games concluded in either overtime or the shootout. Further, regardless of team quality, home teams’ odds of winning were moderately lower when games concluded in the shootout rather than overtime. ConclusionsThe shootout may affect home team players' psychological and behavioural states, generally resulting in a decrease in home teams’ odds of winning in the shootout relative to overtime.

Relationship of Physiological Fitness Tests and Early Career Hockey Success in Elite Ice Hockey Players

Talent identification in professional sport is an important component for building a successful team. In an effort to improve athlete identification, physiological fitness assessments are included in a number of leagues, and attempts have been made to quantify the predictive ability of individual tests. In the National Hockey League (NHL), physiological fitness measures have been shown to correlate with draft selection order, but less subjective rankings of success have previously not been considered. PURPOSE: To determine the predictive ability of draft-age physiological fitness test outcomes to forecast the cumulative total games played within the player’s first 3 consecutive NHL seasons. Games played are an accepted indicator of success at the professional level. METHODS: Multiple linear regression modeling was used with NHL Combine data (1998-2007) for a total of 451 players, who played ≥1 game per year during their first 3 NHL seasons. Separate models were developed for forwards and defense, given the differing physiological profiles and positional demands. RESULTS: For defensemen, the variables of vertical jump (VJ), push-ups, bench press, and body index were included in the final model (p=0.001, r2=0.15). The regression equation to predict number of games played by defensemen over 3yr was: total games= 177 -0.979 (VJ) + 4.068(max push up) -3.87(max bench press) +9.5 (Body index). The only predictive variable for forward players was push up repetitions (p=0.01, r2=0.04); total games =193.1 -2.3(max push-up). CONCLUSION: NHL Combine data was useful for explaining approximately 4% (forward) and 15% (defense) of the variance in games played amongst players who played ≥3yr in the league, suggesting a modest predictive ability. Upper body strength proved an important predictor for both models, while leg power was identified as a predictor only in defensemen. Homogeneity in performance amongst such elite athletes may explain the absence of more traditional measures of physiological fitness (VO2max, anaerobic power) within the predictive models, as a high level of these physiological traits is obligatory for all players who remained in the league at least three years.

Visor use among National Hockey League players and its relationship to on-ice performance

ObjectiveTo assess the use of half and three-quarter visors among National Hockey League (NHL) players and investigate the relationship between skill level and on-ice statistics such as points, penalty minutes...

National Hockey League guaranteed contracts

Purpose – This paper aims to investigate, through the lens of the principal–agent problem, the relationship between payment of National Hockey League (NHL) salaries and player performance during the period of 2005-2011 and explore the inherent issues within the NHL player compensation and incentive structure. Design/methodology/approach – The research adopts a pragmatic philosophy with deductive reasoning. This paper focuses on the NHL season 2005-2011 and undertake analysis of historical player contracts and performance data of 670 players across 29 clubs to undertake liner regression analysis. Findings – This paper quantifies potential inefficiencies of NHL league contracts and defines the parameters of the principal–agent problem. It is identifies that player performance generally increases with salary, is higher in the first year of a contract and despite decreasing over the life of the contract, will usually peak again in the final year of the contract. Research limitations/implications – The research is based around figures from 2005-2011 and secondary statistical data. The study captures quantitative data but does not allow for an exploration of the qualitative perspective to the problem. Practical implications – Entry-level or first contracts are good for all teams and players because they provide incentive to perform and a reduction of risk to the team should a player not perform to expectations. The same can be said for players at the other end of the spectrum. Although not typically used much, performance bonuses for players over the age of 35 allow clubs to “take a chance” on a player and the player can benefit by reaching attainable bonuses. These findings therefore provide contributions to the practicing managers and coaches of NHL teams who can consider the results to help shape their approach to management of players and the planning of teams and succession planning for talent. Originality/value – The paper presents a comprehensive and current perspective of the principal–agent problem in NHL and extends the work of Purcell (2009) and Gannon (2009) in understanding player performance enhancement.

A Markov Model for Hockey: Manpower Differential and Win Probability Added

We extend the classic Poisson model of hockey based on score differential and time remaining in the game to include the effect of penalties, and derive the associated Markov win probability model given the goal/manpower differential state at any point in a hockey game. Given data from the 2008/9–2011/12 National Hockey League seasons (a total of 4,920 games) reporting second-by-second goal and manpower differentials (which results in roughly 17.7 million observations), we estimate the state dependent transition rates and win probabilities. The data reveal that even after controlling for the home edge afforded by visiting teams being penalized more frequently than home teams, the goal scoring rate for the home team is higher than for visiting teams at most equivalent manpower differential levels. We use the model to develop a new win probability added metric for evaluating individual players based on their incremental contribution to the probability of winning and illustrate its use and conservation properties.

Competing process hazard function models for player ratings in ice hockey

Evaluating the overall ability of players in the National Hockey League (NHL) is a difficult task. Existing methods such as the famous "plus/minus" statistic have many shortcomings. Standard linear regression methods work well when player substitutions are relatively uncommon and scoring events are relatively common, such as in basketball, but as neither of these conditions exists for hockey, we use an approach that embraces the unique characteristics of the sport. We model the scoring rate for each team as its own semi-Markov process, with hazard functions for each process that depend on the players on the ice. This method yields offensive and defensive player ability ratings which take into account quality of teammates and opponents, the game situation, and other desired factors, that themselves have a meaningful interpretation in terms of game outcomes. Additionally, since the number of parameters in this model can be quite large, we make use of two different shrinkage methods depending on the question of interest: full Bayesian hierarchical models that partially pool parameters according to player position, and penalized maximum likelihood estimation to select a smaller number of parameters that stand out as being substantially different from average. We apply the model to all five-on-five (full-strength) situations for games in five NHL seasons.