Applications of Statistical Physics to the Social and Economic Sciences

This thesis applies statistical physics concepts and methods to quantitatively analyze socioeconomic systems. For each system we combine theoretical models and empirical data analysis in order to better understand the real-world system in relation to the complex interactions between the underlying human agents. This thesis is separated into three parts: (i) response dynamics in financial markets, (ii) dynamics of career trajectories, and (iii) a stochastic opinion model with quenched disorder. In Part I we quantify the response of U.S. markets to financial shocks, which perturb markets and trigger “herding behavior” among traders. We use concepts from earthquake physics to quantify the decay of volatility shocks after the “main shock.” We also find, surprisingly, that we can make quantitative statements even before the main shock. In order to analyze market behavior before as well as after “anticipated news” we use Federal Reserve interest-rate announcements, which are regular events that are also scheduled in advance. In Part II we analyze the statistical physics of career longevity. We construct a stochastic model for career progress which has two main ingredients: (a) random forward progress in the career and (b) random termination of the career. We incorporate the rich-get-richer (Matthew) effect into ingredient (a), meaning that it is easier to move forward in the career the farther along one is in the career. We verify the model predictions analyzing data on 400,000 scientific careers and 20,000 professional sports careers. Our model highlights the importance of early career development, showing that many careers are stunted by the relative disadvantage associated with inexperience. In Part III we analyze a stochastic two-state spin model which represents a system of voters embedded on a network. We investigate the role in consensus formation of “zealots”, which are agents with time-independent opinion. Our main result is the unexpected finding that it is the number and not the density of zealots which determines the steady-state opinion polarization. We compare our findings with results for United States Presidential elections

Inverse Dynamics Analysis of Youth Pitching Arm Kinetics Using Body Composition Imaging

This study’s objectives were to: (1) assess whether dual energy X-ray absorptiometry (DXA)-mass inverse dynamics (ID) alters predictions of youth pitching arm kinetics and (2) investigate correlations between kinetics and body composition. Eighteen 10- to 11-year-olds pitched 10 fastballs. DXA scans were conducted to obtain participant-specific upper arm, forearm, and hand masses. Pitching arm segment masses and kinetics calculated with scaled and DXA masses were compared with paired t-tests and correlations were investigated with linear regression. Hand (p \u3c 0.001) and upper arm (p \u3c 0.001) DXA masses were greater, while forearm (p \u3c 0.001) DXA masses were lesser, than their scaled masses. Shoulder compressive force (p \u3c 0.001), internal rotation torque (p \u3c 0.001), and horizontal adduction torque (p = 0.002) increased when using DXA masses. Shoulder compressive force correlated with body mass (p \u3c 0.001) and body mass index (BMI; p = 0.002) and elbow varus torque correlated with body mass (p \u3c 0.05). The main conclusions were that (1) using participant-specific mass ratios leads to different predictions of injury-related pitching arm kinetics and, thus, may improve our understanding of injury risk factors; and (2) pitching arm kinetics were correlated with body composition measures and a relatively high total body mass and/or BMI may increase shoulder and/or elbow injury risk

Integrated Baseball in Kansas during the Sport’s Era of Segregation, 1865–1945

Black athletes were barred from playing baseball in the major and minor leagues prior to 1946 with few exceptions. The implementation of the color line in organized baseball during the nineteenth century has been the focus of thorough research. Less studied is integrated baseball among independent town teams, and this research has focused on particular players or circumstances rather than an entire state or region across a broad span of baseball history. Integrated teams in Kansas provide a unique opportunity to examine their history at these larger scales. Prior to 1946, major league baseball was essentially concentrated east of the Mississippi River, which placed Kansas on the sport’s broad western frontier. Also, the role of Kansas in the prelude to the Civil War placed the state on the boundary separating North from South. In addition to the geographical context, most newspapers published in the state prior to 1923 and several published after that year have been digitized. Collectively, these circumstances make Kansas well suited to serve as a case study of the broader history of integrated baseball from 1865 to 1945. This book begins with biographies of more than 80 Black baseballists who played or umpired games with white or predominantly white town teams and minor league clubs, as well as predominantly Black teams that had white players. With the foundation provided by these experiences, the questions of why, when, and where integrated town teams took the field are examined and placed within the context of segregation and exclusion across the broader community.https://scholars.fhsu.edu/all_monographs/1032/thumbnail.jp

The Biomechanics and Evolution of High-Speed Throwing

Throwing with power and accuracy is a uniquely human behavior and a potentially important mode of early hunting. Chimpanzees, our closest living relatives, do occasionally throw, although with much less velocity. At some point in our evolutionary history, hominins developed the ability to produce high performance throws. The anatomical changes that enable increased throwing ability are poorly understood and the antiquity of this behavior is unknown. In this thesis, I examine how anatomical shifts in the upper body known to occur during human evolution affect throwing performance. I propose a new biomechanical model for how humans amplify power during high-speed throwing using elastic energy stored and released in the throwing shoulder. I also propose and experimentally test a series of functional hypotheses regarding how four key shifts in upper body anatomy affect throwing performance: increased torso rotational mobility, laterally oriented shoulders, lower humeral torsion, and increased wrist hyperextensability. These hypotheses are tested by collecting 3D body motion data during throws performed by human subjects in whom I varied anatomical parameters using restrictive braces to examine their effects on throwing kinematics. These data are broken down using inverse dynamics analysis into the individual motions, velocities, and forces acting around each joint axis. I compare performance at each joint across experimental conditions to test hypotheses regarding the relationship between skeletal features and throwing performance. I also developed and tested a method for predicting humeral torsion using range of motion data, allowing me to calculate torsion in my subjects and determine its effect on throwing performance. My results strongly support an important role for elastic energy storage in powering humans’ uniquely rapid throwing motion. I also found strong performance effects related to anatomical shifts in the torso, shoulder, and arm. When used to interpret the hominin fossil record, my data suggest high-speed throwing ability arose in a mosaic-like fashion, with all relevant features first present in Homo erectus. What drove the evolution of these anatomical shifts is unknown, but as a result the ability to produce high-speed throws was available for early hunting and likely provided an adaptive advantage in this context.Anthropolog

A New Measure of Distributive Justice by Data Envelopment Analysis

Traditionally, distributive justice has been measured with multiple question items to which respondents indicate the degree to which their working situation corresponds with those described in the question items. This article proposes an alternative method to measure distributive justice, using the data envelopment analysis (DEA) approach. We apply an efficiency measure calculated in DEA for the inputs/outcomes ratio to judge distributive justice in the organization. Using the data collected from accounting workers who live in the Tokyo metropolitan area, the results of correlation analysis show that this new measure of distributive justice has significant positive correlations with all three satisfaction variables in a male sample, and with one satisfaction variable in a female sample, providing some justification for using this new variable as a measure of distributive justice

Ranking Players by DEA: An analysis of Czech and Danish football

Team managers and coaches need to choose the best players. The selection relies mainly on the cost and performance of the entire team. It is a common practice that several key players contribute to the overall results of the football team. The quality of players is one of the crucial features determining the failure or success of a sports team. The present article focuses on measuring player efficiency in the Czech and Danish top football competitions during the 2015/16 to 2019/20 seasons. The presented research aims to identify the most technically efficient players, considering their position on the field. The authors used an input-oriented model of data envelopment analysis and subsequently also cluster analysis to determine the best football players. The following article may be of interest to football club managers, football analysts, economists and others interested in the business of football because it combines two relatively simple methods of measuring the efficiency of football players

Antitrust Analysis of Sports Leagues

I present an overview of the antitrust literature on sports leagues, with particular emphasis on the National Collegiate Athletic Association, the National Football League, Major League Baseball, the National Basketball Association, and the National Hockey League, as well as on sanctioning organizations such as NASCAR. I review the major antitrust court decisions, the commentaries of the leading antitrust experts on these decisions, and the extensive sports economics literature touching on issues raised in these cases, particularly empirical studies assessing the anticompetitive and procompetitive effects of various league rules and policies. I also review the broader industrial organization literature on issues such as factors affecting the stability of joint ventures. I conclude with a summary of proposals for addressing the monopoly power of sports leagues.antitrust; sports leagues

This Sporting Life: Sports and Body Culture in Modern Japan

Yale CEAS Occasional Publication Series - Volume 1 Sports in Japan have long been embedded in community life, the educational system, the mass media, the corporate structures, and the nationalist sentiments of modern Japan. For over a century, they have been a crucial intersection of school pedagogy, corporate aims, media constructions, gender relations, and patriotic feelings. The chapters in this book highlight a wide range of sports, and together, they offer a significant window on to the ways that the sporting life animates the institutions of modern Japan.https://elischolar.library.yale.edu/ceas_publication_series/1000/thumbnail.jp