<論文>理系の誰が高収入なのか? : SSM2005 データにもとづく文系・理系の年収比較

Abstract

This paper aims to compare the average incomes of three groups of Japanese university graduates: medical, STEM (science, technology, engineering, mathematics), and non-STEM/M graduates. Previous studies have shown that graduates of STEM/M (STEM and medicine) earn more than non-STEM/M graduates, and have argued that this difference is because STEM graduates create higher additional value than non-STEM/M graduates. However, those studies did not consider variables that should be important determinants of income in the Japanese labor market. Moreover, there are strong doubts about the interpretation that the higher incomes of STEM/M graduates result from the higher additional value STEM graduates create. Drawing on the 2005 Social Stratification and Social Mobility national survey data, this paper examines whether STEM/M graduates earn more than non-STEM/M graduates, after controlling for other important determinants of income. The results from a multiple regression analysis estimating the effect of STEM/M on income shows that STEM/M graduates earn more than non-STEM/M graduates. When separating medical and STEM graduates, however, the estimated effect of a STEM major is not statistically significant and its value is low (1% higher than non-STEM/M). Moreover, when the sample is divided into men and women, there is a significant gender discrepancy in the effect of a STEM major: male STEM graduates earn more than male non-STEM/M graduates while female STEM graduates earn much less than female non-STEM/M graduates.