國內外針對棒球績效表現的研究不在少數，但針對美國職棒大聯盟球員在簽約前後與績效表現之間的關聯性之探討甚少。因此，本研究欲藉由資料包絡分析法，衡量符合本研究定義之優渥複數年合約之球員，在簽約前後與績效表現之關聯性，以及探討簽約前之績效表現是否構成合約內容之主要因素。 本研究以1999年至2006年共八年期間，在此期間有簽訂符合本研究定義之「優渥複數年合約」之球員為研究對象。實證結果顯示投手與野手皆無在簽訂優渥複數年合約前投入較多的努力，在簽約後績效開始下滑的情況；最後，投手合約薪資的決定因素為簽約前的績效、球齡和勝場數；合約長度的決定因素為球齡；合約總薪資的決定因素為球齡和勝場數。野手合約薪資的決定因素為球齡；合約長度的決定因素亦為球齡；合約總薪資的決定因素為簽約前的績效、球齡和得獎與否。 / Many scholars did researches on performance of baseball players before, however, few of them mentioned MLB players’ performance before and after signing contracts. By using DEA (Data Envelopment Analysis) techniques to measure MLB players’ changes of efficiency defined as signing ‘high salary and multi-year contracts”. And to find out the most important factors in determining the players’ salary in MLB in order to provide useful information for club owners and players in the future. The sample year includes MLB players from 1996 to 2001 who sign high salary and multi-year contracts. On the other hand, the results show that the main factors in determining the pitchers’ salaries are wins and tenure respectively and the main factors in determining the fielders’ salaries are performance, prize and tenure.