本文利用Probit模型，實證估計影響醫師防禦性醫療行為傾向的因素。實證資料 係來自對臺灣地區西醫師所進行的問卷調查結果，共有 1,131 個樣本。 迴歸分析的結果發 現，曾經有過醫療糾紛經驗的醫師，較傾向於採行防禦性的醫療行為，而且愈是最近發生的 醫療糾紛，此種傾向愈大。除此之外，醫師執業科別的差異，亦對防禦性醫療行為傾向，具 有顯著的解釋能力。這方面的主要發現，有下列兩項：１．精神科、麻醉科、復健科、放射 線科與病理科等科別的醫師，較少採取防禦性的醫療行為；２．外科與婦產科的醫師，較常 採取增加檢驗或治療的防禦性醫療行為。上述研究結果證實，醫療糾紛風險確實會改變醫師 的執業行為。

　　　　　This paper presents a probit model to estimate the determinants of physician's propensity of practicing defensive medicine in Taiwan. The empirical data were drawn from a national physician survey conducted in November 1991. The survey data included 1,131 physicians and had a 18% response rate. The empirical results indicate that physicians who have experiences of medical malpractice claims are more likely to practice defensive medicine. The more recent is the experience of claims, the higher is the propensity of practicing defensive medicine. Also, the results show that surgeons, obstetricians and gynecologists are more likely to prescribe more tests and treatment procedures. Overall, the empirical evidence suggests that the risk of medical liability actually forces the physicians to change their practice behaviors.