Predicting probabilities for the 2010 FIFA World Cup games using a Poisson-Gamma model

In this paper, we provide probabilistic predictions for soccer games of the 2010 FIFA World Cup modelling the number of goals scored in a game by each team. We use a Poisson distribution for the number of goals for each team in a game, where the scoring rate is considered unknown. We use a Gamma distribution for the scoring rate and the Gamma parameters are chosen using historical data and difference among teams defined by a strength factor for each team. The strength factor is a measure of discrimination among the national teams obtained from their memberships to fuzzy clusters. The clusters are obtained with the use of the Fuzzy C-means algorithm applied to a vector of variables, most of them available on the official FIFA website. Static and dynamic models were used to predict the World Cup outcomes and the performance of our predictions was evaluated using two comparison methods.     

Soccer matches as experiments: how often does the ‘best’ team win?

Models in which the number of goals scored by a team in a soccer match follow a Poisson distribution, or a closely related one, have been widely discussed. We here consider a soccer match as an experiment to assess which of two teams is superior and examine the probability that the outcome of the experiment (match) truly represents the relative abilities of the two teams. Given a final score, it is possible by using a Bayesian approach to quantify the probability that it was or was not the case that ‘the best team won’. For typical scores, the probability of a misleading result is significant. Modifying the rules of the game to increase the typical number of goals scored would improve the situation, but a level of confidence that would normally be regarded as satisfactory could not be obtained unless the character of the game was radically changed.     

Non-parametric procedure for knockout tournaments

In a seeded knockout tournament, where teams have some preassigned strength, do we have any assurances that the best team in fact has won? Is there some insight to be gained by considering which teams beat which other teams solely examining the seeds? We pose an answer to these questions by using the difference in the seeds of the two players as the basis for a test statistic. We offer several models for the underlying probability structure to examine the null distribution and power functions and determine these for small tournaments (less than five teams). One structure each for 8 teams and 16 teams is examined, and we conjecture an asymptotic normal distribution for the test statistic.     

MODELLING THE 2004 SUPER 12 RUGBY UNION COMPETITION

This paper uses Bayesian methods via WinBUGS to model round robin play in the 2004 Super 12 Rugby Union competition in order to explore home advantage and how that impacts the outcome of the competition. The scores from the games are decomposed into counts of converted and unconverted tries, penalties and drop goals and are modelled as Poisson random variables with a log link. The dependent variables are the offensive and defensive capabilities of the teams along with terms for home advantage. The model is used to ascertain the effects of home advantage on the standings of the teams in the competition and, from that, how fairness in the competition could be improved.     

Are football referees really biased and inconsistent?: evidence on the incidence of disciplinary sanction in the English Premier League

Summary.  The paper presents a statistical analysis of patterns in the incidence of disciplinary sanction (yellow and red cards) that were taken against players in the English Premier League over the period 1996–2003. Several questions concerning sources of inconsistency and bias in refereeing standards are examined. Evidence is found to support a time consistency hypothesis, that the average incidence of disciplinary sanction is predominantly stable over time. However, a refereeing consistency hypothesis, that the incidence of disciplinary sanction does not vary between referees, is rejected. The tendency for away teams to incur more disciplinary points than home teams cannot be attributed to the home advantage effect on match results and appears to be due to a refereeing bias favouring the home team.     

Rating teams and analysing outcomes in one-day and test cricket

Summary.  Multiple linear regression techniques are applied to determine the relative batting and bowling strengths and a common home advantage for teams playing both innings of international one-day cricket and the first innings of a test-match. It is established that in both forms of the game Australia and South Africa were rated substantially above the other teams. It is also shown that home teams generally enjoyed a significant advantage. Using the relative batting and bowling strengths of teams, together with parameters that are associated with common home advantage, winning the toss and the establishment of a first-innings lead, multinomial logistic regression techniques are applied to explore further how these factors critically affect outcomes of test-matches. It is established that in test cricket a team's first-innings batting and bowling strength, first-innings lead, batting order and home advantage are strong predictors of a winning match outcome. Contrary to popular opinion, it is found that the team batting second in a test enjoys a significant advantage. Notably, the relative superiority of teams during the fourth innings of a test-match, but not the third innings, is a strong predictor of a winning outcome. There is no evidence to suggest that teams generally gained a winning advantage as a result of winning the toss.     

创新导向团队薪酬及其契约设计的实验研究

团队合作是现代企业创新活动的主要工作方式,团队薪酬的模式选择与契约设计对于企业创新具有重要意义。本文设计了一项奶茶店团队经营实验,采用实验研究的方法检验不同模式下团队薪酬对创新绩效的影响,以及团队薪酬中探索性薪酬的授予范围和业绩考核强度对创新绩效的影响。结果表明:与固定薪酬和浮动薪酬相比,探索性薪酬模式下实验团队的创新投入水平更高、创新产出更多;对于授予范围来说,与不授予探索性薪酬、较小范围授予探索性薪酬及全部授予探索性薪酬模式相比,较大范围授予探索性薪酬时实验团队的创新投入水平更高、创新产出更多;对于业绩考核强度来说,与宽松型业绩考核强度和严格型业绩考核强度相比,适中型业绩考核强度下实验团队的创新投入水平更高、创新产出更多;团队的风险规避程度同样影响创新绩效,探索性薪酬模式下风险偏好的团队普遍有更好的创新投入表现。本文的研究丰富了团队薪酬及其契约设计与创新绩效的相关文献,为企业设计创新导向的团队薪酬契约提供了理论依据。     

Modelling the evolution of distributions: an application to Major League baseball

Summary.  We develop Bayesian techniques for modelling the evolution of entire distributions over time and apply them to the distribution of team performance in Major League baseball for the period 1901–2000. Such models offer insight into many key issues (e.g. competitive balance) in a way that regression-based models cannot. The models involve discretizing the distribution and then modelling the evolution of the bins over time through transition probability matrices. We allow for these matrices to vary over time and across teams. We find that, with one exception, the transition probability matrices (and, hence, competitive balance) have been remarkably constant across time and over teams. The one exception is the Yankees, who have outperformed all other teams.     

Convergent Evolution of Innovative Teams in Technical Services

Abstract

In recent years UNC-Chapel Hill Libraries, Duke University Libraries, and NC State University Libraries each formed a new team in response to the increasing need to repurpose and reuse data and metadata in and across domains, systems, and environments in new ways. During this session at NC Serials 2019 the speakers described their teams, how those teams came about, and their responsibilities; discussed similarities and differences across their teams; and shared communication strategies, lessons, and opportunities they’ve learned so far. This report captures the discussions that occurred during this session.     

Construction of a semi-Markov model for the performance of a football team in the presence of missing data

Using play-by-play data from the very beginning of the professional football league in Turkey, a semi-Markov model is presented for describing the performance of football teams. The official match results of the selected teams during 55 football seasons are used and winning, drawing and losing are considered as Markov states. The semi-Markov model is constructed with transition rates inferred from the official match results. The duration between the last match of a season and the very first match of the following season is much longer than any other duration during the season. Therefore these values are considered as missing values and estimated by using expectation–maximization algorithm. The effect of the sojourn time in a state to the performance of a team is discussed as well as mean sojourn times after losing/winning are estimated. The limiting probabilities of winning, drawing and losing are calculated. Some insights about the performance of the selected teams are presented.     

LM Test of Neglected Correlated Random Effects and Its Application

This article aims at achieving two distinct goals. The first is to extend the existing LM test of overdispersion to the situation where the alternative hypothesis is characterized by the correlated random effects model. We obtain a result that the test against the random effects model has a certain max-min type optimality property. We will call such a test the LM test of overdispersion. The second goal of the article is to draw a connection between panel data analysis and the analysis of multiplicity of equilibrium in games. Because such multiplicity can be viewed as a particular form of neglected heterogeneity, we propose an intuitive specification test for a class of two-step game estimators.     

How to improve a team's position in the FIFA ranking? A simulation study

In this paper, we study the efficacy of the official ranking for international football teams compiled by FIFA, the body governing football competition around the globe. We present strategies for improving a team's position in the ranking. By combining several statistical techniques, we derive an objective function in a decision problem of optimal scheduling of future matches. The presented results display how a team's position can be improved. Along the way, we compare the official procedure to the famous Elo rating system. Although it originates from chess, it has been successfully tailored to ranking football teams as well.     

Robust Bayesian methodology with applications in credibility premium derivation and future claim size prediction

Robust Bayesian methodology deals with the problem of explaining uncertainty of the inputs (the prior, the model, and the loss function) and provides a breakthrough way to take into account the input’s variation. If the uncertainty is in terms of the prior knowledge, robust Bayesian analysis provides a way to consider the prior knowledge in terms of a class of priors \(\varGamma \) and derive some optimal rules. In this paper, we motivate utilizing robust Bayes methodology under the asymmetric general entropy loss function in insurance and pursue two main goals, namely (i) computing premiums and (ii) predicting a future claim size. To achieve the goals, we choose some classes of priors and deal with (i) Bayes and posterior regret gamma minimax premium computation, (ii) Bayes and posterior regret gamma minimax prediction of a future claim size under the general entropy loss. We also perform a prequential analysis and compare the performance of posterior regret gamma minimax predictors against the Bayes predictors.     

Temporal patterns in twenty years of canadian homicides

Detailed data describing all homicides in Canada known to the police are collected by Statistics Canada. In this study, three independent teams of analysts search for seasonality and other temporal patterns in homicide rates and frequencies between 1961 and 1980.     

Dynamic factor structure of team performances in Liga MX

Team performance of the Mexican Football League (Liga MX), measured as the percentage of the total points obtained during each short tournament, is analyzed using Dynamic Factor Models (DFMs). The estimation of the common components is carried out with Principal Components and the stochastic nature of the DFM is studied through Panel Analysis of Non-stationarity in Idiosyncratic and Common Components. The results reveal that there are two common factors, one being possibly non-stationary. These factors show an interesting dynamic behavior in the league and allow to split the teams into two groups, namely, top competitors and emerging or relegated teams. Some discussion is given in this direction.     

Analysis of the importance of on-field covariates in the German Bundesliga

In modern football, various variables as, for example, the distance a team runs or its percentage of ball possession, are collected throughout a match. However, there is a lack of methods to make use of these on-field variables simultaneously and to connect them with the final result of the match. This paper considers data from the German Bundesliga season 2015/2016. The objective is to identify the on-field variables that are connected to the sportive success or failure of the single teams. An extended Bradley–Terry model for football matches is proposed that is able to take into account on-field covariates. Penalty terms are used to reduce the complexity of the model and to find clusters of teams with equal covariate effects. The model identifies the running distance to be the on-field covariate that is most strongly connected to the match outcome.     

Patterns of NBA team performance from 1950 to 1998

This paper examines team performance in the NBA over the last five decades. It was motivated by two previous observational studies, one of which studied the winning percentages of professional baseball teams over time, while the other examined individual player performance in the NBA. These studies considered professional sports as evolving systems, a view proposed by evolutionary biologist Stephen Jay Gould, who wrote extensively on the disappearance of .400 hitters in baseball. Gould argued that the disappearance is actually a sign of improvement in the quality of play, reflected in the reduction of variability in hitting performance. The previous studies reached similar conclusions in terms of winning percentages of baseball teams, and performance of individual players in basketball. This paper uses multivariate measures of team performance in the NBA to see if similar characteristics of evolution can be observed. The conclusion does not appear to be clearly affirmative, as in previous studies, and possible reasons for this are discussed.     

Power Ratings for NCAA Division II Football

ABSTRACT

There is an abundance of entities that disseminate power ratings for NCAA Division I-A and I-AA football teams. This is not true for the NCAA Division II level. Statistical data on all NCAA Divisions II football games for two years were examined to develop a rating system. Several statistical techniques were performed on the data. Ultimately, the ratings were based on won-lost percentage, margin of victory, strength of schedule, and quality wins. Results are given for the 2001 and 2002 seasons. Ratings for the 2002 season for Divisions I-A and I-AA are also given using the techniques developed.     

中国家庭养育目标的影响因素及其差异分析

基于2010年中国家庭动态跟踪调查(CFPS)数据库,分析养育目标在城乡之间以及不同少儿年龄组之间的差异,并利用Logistic回归模型探讨家庭养育目标的影响因素。结果表明:养育目标在城乡之间有显著差异,但在不同的少儿年龄组之间无显著差异;父亲职务、父母受教育程度及母亲户口状况不同程度地影响着"在自己年老时得到帮助"、"延续家族香火"、"从经济上帮助家庭"、"使家庭在自己的生活中更重要"和"增加亲属联系"这五个养育目标。     

自主探究模式下英语学习目标定向的统计研究

通过对自主探究学习模式的实证研究,分析、总结了学习者在该模式下的英语学习目标定向的构成,探讨各种学习目标定向与教学绩效的关系,发现自主探究模式可以显著提高外语教学绩效。在此模式下,学习者的学习目标定向以成绩目标定向为主。与掌握目标定向相比,成绩目标定向的确可以显著提高教学绩效。