Spatial regression analysis of political gender gap in Japan

Abstract

Internationally, it has been repeatedly pointed out that the proportion of female members in the Diet and the local assemblies is extremely low in Japan. This is called a political gender gap. We analyzed the relationships between socioeconomic indicators and this political gender gap, and underlying causes using several spatial regression models. Prefectures are geographically connected; so, they can influence each other. Therefore, we incorporated geographical relationships between prefectures into the model. We found that a high proportion of women in a particular prefectural assembly was associated with a low proportion of women in adjacent prefectural assemblies. Thus, competition and repulsion exist between the adjacent prefectural assemblies. Furthermore, several series of analyses using spatial regression models showed that the impact of the political gender gap in a particular prefecture spread to adjacent prefectures, but not further. We found that considering prefectural spatial autocorrelations was important while examining the political gender gap, and previous studies that did not consider spatial autocorrelation might have been biased. However, here we were able to better explain the background of real-world phenomena occurring in the real world by applying spatial regression models.