2005年5月健保局將自然產給付加倍，調整至與剖腹產給付一致，期望透過自然產給付增加，來降低剖腹產率並改善醫療品質。這自然產給付增加提供了一個檢視給付提高對醫療品質改善機會。本文使用2004與2006年生產案件，以健保給付當作醫師所得的替代變數，醫療品質則以剖腹產率、住院天數、再住院率進行觀察，分析醫師所得增加和醫療品質間因果關係。爲控制醫療時無法觀察因子，估計時選用初產產婦，並採用「一階差分」方式來排除內生性偏誤。結果顯示給付增加對剖腹產率沒有顯著關係，但原先自然產比例較高醫師剖腹產率卻有降低；另外，自然產再住院率也顯著下降。我們進一步針對幾個解釋剖腹產偏低效果進行檢驗，發現產婦個人偏好剖腹產是一個可能原因。最後，我們發現這給付調整效果並未外溢到同醫院的婦科、兒科治療。

In May 2005, Bureau of National Health Insurance doubled the reimbursement for vaginal delivery to the same rate as paid for cesarean section (csection) in order to reduce the c-section rate and improve the quality of care. This reimbursement adjustment provides an excellent opportunity to examine whether such a payment increase can improve healthcare quality. Using obstetric cases of firstborns in 2004 and 2006 from National Health Insurance Data, this study examines if there was a negative relation between quality indicators (e.g. c-section, re-admission, and length of stay) and doctor’s income, measured in terms of payments paid by NHI for baby delivery. To control for the endogenous bias, the study employs “first-difference” methods to attenuate the bias arising from unobserved factors, and restricts the sample to firstborn babies. Our results indicate that the doctor’s income and c-section rate is statistically uncorrelated on the whole, but negatively related for doctors who previously had a lower percentage of c-sections. Additionally, we found the payment reduces both the 14 and 30 days re-admission after vaginal delivery. Furthermore, the analysis indicates that one explanation— a c-section is preferred by women for the sake of personal reasons— is largely consistent with our empirical findings. Finally, we found the effect of the payment increase did not spill over to gynecology or pediatric services in the same hospital.