Journal of Quantitative Analysis in Sports最新文献_第9页

Modeling time loss from sports-related injuries using random effects models: an illustration using soccer-related injury observations 使用随机效应模型模拟运动相关损伤的时间损失:使用足球相关损伤观察的插图

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Journal of Quantitative Analysis in Sports Pub Date : 2020-09-25 DOI: 10.1515/JQAS-2019-0030

C. Avinash, DiPietro Loretta, Young Heather, Elmi Angelo

{"title":"Modeling time loss from sports-related injuries using random effects models: an illustration using soccer-related injury observations","authors":"C. Avinash, DiPietro Loretta, Young Heather, Elmi Angelo","doi":"10.1515/JQAS-2019-0030","DOIUrl":"https://doi.org/10.1515/JQAS-2019-0030","url":null,"abstract":"In assessments of sports-related injury severity, time loss (TL) is measured as a count of days lost to injury and analyzed using ordinal cut points. This approach ignores various athlete and event-specific factors that determine the severity of an injury. We present a conceptual framework for modeling this outcome using univariate random effects count or survival regression. Using a sample of US collegiate soccer-related injury observations, we fit random effects Poisson and Weibull Regression models to perform “severity-adjusted” evaluations of TL, and use our models to make inferences regarding the recovery process. Injury site, injury mechanism and injury history emerged as the strongest predictors in our sample. In comparing random and fixed effects models, we noted that the incorporation of the random effect attenuated associations between most observed covariates and TL, and model fit statistics revealed that the random effects models (AICPoisson = 51875.20; AICWeibull-AFT = 51113.00) improved model fit over the fixed effects models (AICPoisson = 160695.20; AICWeibull-AFT = 53179.00). Our analyses serve as a useful starting point for modeling how TL may actually occur when a player is injured, and suggest that random effects or frailty based approaches can help isolate the effect of potential determinants of TL.","PeriodicalId":16925,"journal":{"name":"Journal of Quantitative Analysis in Sports","volume":"15 1","pages":"221-235"},"PeriodicalIF":0.8,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82611389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Smart kills and worthless deaths: eSports analytics for League of Legends 聪明的杀戮和毫无价值的死亡:《英雄联盟》电子竞技分析

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Journal of Quantitative Analysis in Sports Pub Date : 2020-09-21 DOI: 10.1515/jqas-2019-0096

Philip Z. Maymin

{"title":"Smart kills and worthless deaths: eSports analytics for League of Legends","authors":"Philip Z. Maymin","doi":"10.1515/jqas-2019-0096","DOIUrl":"https://doi.org/10.1515/jqas-2019-0096","url":null,"abstract":"Abstract Vast data on eSports should be easily accessible but often is not. League of Legends (LoL) only has rudimentary statistics such as levels, items, gold, and deaths. We present a new way to capture more useful data. We track every champion’s location multiple times every second. We track every ability cast and attack made, all damages caused and avoided, vision, health, mana, and cooldowns. We track continuously, invisibly, remotely, and live. Using a combination of computer vision, dynamic client hooks, machine learning, visualization, logistic regression, large-scale cloud computing, and fast and frugal trees, we generate this new high-frequency data on millions of ranked LoL games, calibrate an in-game win probability model, develop enhanced definitions for standard metrics, introduce dozens more advanced metrics, automate player improvement analysis, and apply a new player-evaluation framework on the basic and advanced stats. How much does an individual contribute to a team’s performance? We find that individual actions conditioned on changes to estimated win probability correlate almost perfectly to team performance: regular kills and deaths do not nearly explain as much as smart kills and worthless deaths. Our approach offers applications for other eSports and traditional sports. All the code is open-sourced.","PeriodicalId":16925,"journal":{"name":"Journal of Quantitative Analysis in Sports","volume":"19 3 1","pages":"11 - 27"},"PeriodicalIF":0.8,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83284203","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19

The influence of field size, goal size and number of players on the average number of goals scored per game in variants of football and hockey: the Pi-theorem applied to team sports 场地大小、球门大小和球员人数对足球和曲棍球比赛每场平均进球数的影响:pi定理在团队运动中的应用

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Journal of Quantitative Analysis in Sports Pub Date : 2020-09-21 DOI: 10.1515/JQAS-2020-0009

J. Blondeau

{"title":"The influence of field size, goal size and number of players on the average number of goals scored per game in variants of football and hockey: the Pi-theorem applied to team sports","authors":"J. Blondeau","doi":"10.1515/JQAS-2020-0009","DOIUrl":"https://doi.org/10.1515/JQAS-2020-0009","url":null,"abstract":"Abstract In this paper, we investigate the correlation between the main physical characteristics of eight variants of football and hockey (such as field size, goal size, player velocity, ball velocity, player density, and game duration) and the resulting average numbers of goals scored per game. To do so, the Pi-theorem in physics is extended to sport science and a non-dimensional parameter of interest is defined. It is based on the ratio between the duration of the game and the order of magnitude of the time needed to cross the midfield, which depends on the average velocity of the ball and the players, the player density and the size of the goals. An excellent correlation is found between the proposed parameter and the average number of goals scored per game during recent international competitions. Using the derived correlation, the effect of any modification of the main characteristics of football and hockey (and their variants) on the scoring pace can be assessed. For instance, it can be predicted that decreasing the length of football fields by 20 m would raise the average number of goals scored to 3.6 (±0.6) per game, versus the 2.6 goals scored during the most recent men’s World Cup.","PeriodicalId":16925,"journal":{"name":"Journal of Quantitative Analysis in Sports","volume":"46 1","pages":"145 - 154"},"PeriodicalIF":0.8,"publicationDate":"2020-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74968437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Swing shift: a mathematical approach to defensive positioning in baseball 挥棒移位:棒球中防守位置的数学方法

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Journal of Quantitative Analysis in Sports Pub Date : 2020-09-15 DOI: 10.1515/jqas-2020-0027

Elizabeth L. Bouzarth, B. Grannan, John M Harris, A. Hartley, K. Hutson, E. Morton

{"title":"Swing shift: a mathematical approach to defensive positioning in baseball","authors":"Elizabeth L. Bouzarth, B. Grannan, John M Harris, A. Hartley, K. Hutson, E. Morton","doi":"10.1515/jqas-2020-0027","DOIUrl":"https://doi.org/10.1515/jqas-2020-0027","url":null,"abstract":"Abstract Defensive repositioning strategies (shifts) have become more prevalent in Major League Baseball in recent years. In 2018, batters faced some form of the shift in 34% of their plate appearances (Sawchik, Travis. 2019. “Don’t Worry, MLB–Hitters Are Killing The Shift On Their Own.” FiveThirtyEight, January 17, 2019. Also available at fivethirtyeight.com/features/dont-worry-mlb-hitters-are-killing-the-shift-on-their-own/). Most teams use a shift that overloads one side of the infield and adjusts the positioning of the outfield. In this work we describe a mathematical approach to the positioning of players over the entire field of play without the limitations of traditional positions or current methods of shifting. The model uses historical data for individual batters, and it leaves open the possibility of fewer than four infielders. The model also incorporates risk penalties for positioning players too far from areas of the field in which extra-base hits are more likely. This work is meant to serve as a decision-making tool for coaches and managers to best use their defensive assets. Our simulations show that an optimal positioning with three infielders lowered predicted batting average on balls in play (BABIP) by 5.9% for right-handers and by 10.3% for left-handers on average when compared to a standard four-infielder placement of players.","PeriodicalId":16925,"journal":{"name":"Journal of Quantitative Analysis in Sports","volume":"1942 1","pages":"47 - 55"},"PeriodicalIF":0.8,"publicationDate":"2020-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91187229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

A contextual analysis of crossing the ball in soccer 足球传中球的语境分析

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Journal of Quantitative Analysis in Sports Pub Date : 2020-09-09 DOI: 10.1515/jqas-2020-0060

Lucas Y. Wu, Aaron Danielson, X. J. Hu, T. Swartz

引用次数: 3

Foul accumulation in the NBA NBA的犯规积累

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Journal of Quantitative Analysis in Sports Pub Date : 2020-09-09 DOI: 10.1515/jqas-2019-0119

Dani Chu

引用次数: 1

Frontmatter

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Journal of Quantitative Analysis in Sports Pub Date : 2020-09-01 DOI: 10.1515/jqas-2020-frontmatter3

引用次数: 0

Corrigendum to: Offensive or defensive play in soccer: a game-theoretical approach 足球中的进攻或防守:一种博弈论的方法

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Journal of Quantitative Analysis in Sports Pub Date : 2020-08-24 DOI: 10.1515/jqas-2020-0080

Daniele Gambarelli, G. Gambarelli, Dries R. Goossens

引用次数: 0

Restoring the real world records in Men’s swimming without high-tech swimsuits 在没有高科技泳衣的情况下恢复男子游泳的真实世界纪录

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Journal of Quantitative Analysis in Sports Pub Date : 2020-08-10 DOI: 10.1515/jqas-2019-0087

Zhenyu Gao, Yixing Li, Zhengxin Wang

{"title":"Restoring the real world records in Men’s swimming without high-tech swimsuits","authors":"Zhenyu Gao, Yixing Li, Zhengxin Wang","doi":"10.1515/jqas-2019-0087","DOIUrl":"https://doi.org/10.1515/jqas-2019-0087","url":null,"abstract":"Abstract The recently concluded 2019 World Swimming Championships was another major swimming competition that witnessed some great progresses achieved by human athletes in many events. However, some world records created 10 years ago back in the era of high-tech swimsuits remained untouched. With the advancements in technical skills and training methods in the past decade, the inability to break those world records is a strong indication that records with the swimsuit bonus cannot reflect the real progressions achieved by human athletes in history. Many swimming professionals and enthusiasts are eager to know a measure of the real world records had the high-tech swimsuits never been allowed. This paper attempts to restore the real world records in Men’s swimming without high-tech swimsuits by integrating various advanced methods in probabilistic modeling and optimization. Through the modeling and separation of swimsuit bias, natural improvement, and athletes’ intrinsic performance, the result of this paper provides the optimal estimates and the 95% confidence intervals for the real world records. The proposed methodology can also be applied to a variety of similar studies with multi-factor considerations.","PeriodicalId":16925,"journal":{"name":"Journal of Quantitative Analysis in Sports","volume":"216 1","pages":"291 - 300"},"PeriodicalIF":0.8,"publicationDate":"2020-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91388380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

A Bayesian adjusted plus-minus analysis for the esport Dota 2 电子竞技《dota2》的贝叶斯调整正负分析

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Journal of Quantitative Analysis in Sports Pub Date : 2020-08-03 DOI: 10.1515/jqas-2019-0103

Nicholas J. Clark, Brian Macdonald, Ian Kloo

{"title":"A Bayesian adjusted plus-minus analysis for the esport Dota 2","authors":"Nicholas J. Clark, Brian Macdonald, Ian Kloo","doi":"10.1515/jqas-2019-0103","DOIUrl":"https://doi.org/10.1515/jqas-2019-0103","url":null,"abstract":"Abstract Analytics and professional sports have become linked over the past several years, but little attention has been paid to the growing field of esports within the sports analytics community. We seek to apply an Adjusted Plus Minus (APM) model, an accepted analytic approach used in traditional sports like hockey and basketball, to one particular esports game: Defense of the Ancients 2 (Dota 2). As with traditional sports, we show how APM metrics developed with Bayesian hierarchical regression can be used to quantify individual player contributions to their teams and, ultimately, use this player-level information to predict game outcomes. In particular, we first provide evidence that gold can be used as a continuous proxy for wins to evaluate a team’s performance, and then use a Bayesian APM model to estimate how players contribute to their team’s gold differential. We demonstrate that this APM model outperforms models based on common team-level statistics (often referred to as “box score statistics”). Beyond the specifics of our modeling approach, this paper serves as an example of the potential utility of applying analytical methodologies from traditional sports analytics to esports.","PeriodicalId":16925,"journal":{"name":"Journal of Quantitative Analysis in Sports","volume":"28 1","pages":"325 - 341"},"PeriodicalIF":0.8,"publicationDate":"2020-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86655099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5