摘要：

This study examines the impact of a monetary incentive policy on teaching preferences and its subsequent effects on teaching effectiveness in higher education. Using decade-long panel datasets from a prestigious university in Taiwan, we employ econometric methods to establish the causal relationship between financial incentives and instructors' teaching language choices. Furthermore, we analyze the teaching effectiveness associated with behavior changes prompted by cash rewards. The findings indicate that while the cash-reward policy successfully motivates instructors to transition from teaching in their native language to English, its effects are delayed, with a time-lag of approximately two years. Additionally, the study highlights potential risks linked to the use of financial incentives, including negative short-term effects on student learning. By providing rigorous empirical evidence, this research contributes to the literature by offering comprehensive insights into incentive-driven teaching behaviors and their implications for educational outcomes.