運動經濟學的三篇論文

Abstract

本論文集結三篇有關美國職棒大聯盟之運動經濟學研究。首篇探討工作過度是否會影響職業棒球選手的生涯與壽命。本文美國職棒大聯盟的球員資料，建構了決定球員工作時間的模型，並藉此計算出球員受到隊友表現影響而産生的工作時間差異，作為計劃外工作時間的估計值。接著，再觀察前一期的計劃外工作時間的多寡是否影響到球員當期的工作時間和個人表現，以及球員的生涯計劃外工作時間是否會對球員的壽命造成傷害。結果顯示，計劃外工作時間較高的大聯盟打者，下一個球季的出場機會將會減少，但投手的出場機會不會受到計劃外工作時間影響。此外，球員也會因為計劃外工作時間的增加而表現下滑、提早退休。然而，工作過度對球員壽命的影響並不明顯。 次篇則探討打者面對使用與自身相異的慣用手投球的投手所佔的優勢（異手優勢）。雖然異手優勢相當顯而易見，但球員表現的數據是同時受到球員天生能力、異手優勢、以及球隊管理策略影響的結果。本研究以西元2000年至2012年間大聯盟球員一百三十萬次的投打對決，提出異手優勢的量化分析及其造成的影響。結果顯示，異手優勢大約佔打者攻擊指數的7%至15%。其次，敵對左投手的比例對實力較差的打者的上場時間所造成的影響，會較其對一般打者造成的影響來得大。最後，若純綷以打擊策略而言，大聯盟應該再增加7.5%的左打者。 最後一篇文章則是檢視球員的季後賽經驗是否會反映在球員的身價上，以線性迴歸來判定曾經參與過季後賽或世界大賽的自由球員是否有較高的薪水。結果顯示，球隊對於在前一個球季贏得世界大賽的投手有較高的需求，但對於打者來說，上一個球季的季後賽經驗不會讓他們獲得更高的薪水。不過打者生涯累積的季後賽經驗比投手的經驗來得更有價值。此外，於季後賽中較常晉級成功的打者，退休的機率也較高，而最常得到世界大賽冠軍的打者的退休機率也是最高的。

This dissertation consists of three essays revolving around Major League Baseball in relation to sports economics. The first essay discusses the effects of overwork on the career and lifespan of professional baseball players. By using the data of players from Major League Baseball (MLB), a working time determination model is used to derive the unplanned working time influenced by a player's teammate performance. Previous unplanned working time is then added to the working time model to see if it influences the future working time and performance of the players. A career average unplanned working time is also calculated to check if it is related to a player's lifespan. The results show that, for MLB batters, high unplanned working time leads to working less in the following season, but the working time of the pitchers seems to be unaffected. Moreover, high unplanned working time makes players perform poorly and more likely to retire. However, the effect of overworked on a player's mortality rate is not obvious. The second essay examines the seemingly self-explanatory concept that batters have an advantage when facing opposite-hand (OH) pitchers. While this opposite-hand (OH) advantage is known to be ex ante, the performance of players is ex post, which contains information about their intrinsic skill, hand (dis)advantage, and teams’ recruiting strategies. Based on more than 1.3 million MLB play-by-play data from 2000 to 2012, we provided a quantitative estimate of the OH advantage and made analyses. The results showed OH advantage accounts for about 7-15% of the ex post on-base plus slugging. Second, marginal batters, both right-handed and left-handed, are more subjective to the proportion of left-handed pitchers than the average batters. Third, there should be 7.5% more left-handed batters in MLB. The third essay investigate the common belief that postseason experience is quite valuable and players with postseason experience are highly esteemed. Regressions are made to determine if the free agent players who had participated in postseason games or won the World Series are more valuable. The results show that teams have higher demand on pitchers who won in the previous World Series, but batters with previous postseason experience do not earn higher salary. However, the batters' career postseason experience is more valuable than the pitchers'. Also, batters who had more experiences in higher stages of postseason will less likely to keep playing in the future, and those who won the Championships more often are most inclined to retire.