Corea del Sur
The legislative bill is a critical factor in assessing whether a representative democracy is functioning well, and the politicians’ ideologies have a significant impact on legislative activities. By investigating complete legislative bills in Korea’s parliament from 2004 to 2016, classified using machine-learning techniques, and politicians’ ideology, measured by the W-NOMINATE method, this study systematically examines the relationship between lawmakers’ ideology and legislation. The results reveal that politicians with a strong conservative ideology propose more bills in general and a higher ratio of bills with an economic focus. The passing and processing rate of welfare-related bills sponsored by conservative lawmakers decrease, while the processing period lengthens. These results are aligned with common beliefs regarding the scope of the legislative agenda according to ideology. As ideological discrepancy increases between individuals and their party increases, the number of bill proposals decreases, and bills are less likely to be processed, reducing legislative productivity and efficiency. This study finds that lawmakers’ ideology has a notable influence on legislative productivity and efficiency. It also suggests that these effects are closely related to both the absolute intensity of a lawmakers’ political ideology and its relative position with respect to the affiliated party.