Chrisse Edmunds and Kristie Phillips, Department of Sociology
Introduction
Every nation has income inequality; however, the degree to which that inequality exists differs between countries. Beckfield (2014) theorizes that countries with high income inequality lack the social supports common in more equal societies. A host of social problems result including poor health outcomes and increased crime rates (Navarro et al. 2003; Elgar & Aitken 2010).
Less is known about how income inequality might be related to educational outcomes. Although there is little empirical work that examines the relationship between income inequality and education, some scholars have hypothesized the importance of income equality for adequate educational opportunities for all students (Chiu 2007). Scholars are concerned regarding the role that growing income inequality in the US will have on educational outcomes (Duncan and Murnane 2014). Considering income inequality continues to rise across most high-income countries (Smeeding 2005), attention to income inequality and education outcomes needs to be given on a broader scale.
In addition, it is important to consider both country- and student-level educational outcomes. Country-level outcomes show the success of students within a country as a whole because they represent how well educational systems affect students from a wide variety of socio-economic backgrounds. Additionally, country-level educational outcomes stimulate attention in the lay audience because these measures serve as benchmarks for cross-country comparison in the media. Including student-level educational outcomes is important because the relationship between a macro, country-level measure and a micro, individual outcome is noteworthy. It is possible that individual students would perform better in a society that addresses its inequality. Achievement gaps signify educational inequality between the highest and lowest SES groups in a nation. These gaps are included in this study to investigate the relationship between income inequality and educational inequality.
An empirical understanding of the relationship between country-level income inequality and educational outcomes will provide evidence supporting the potential importance of changes in national policies that address national income inequality. This relationship is important to understand because increases in country-wide academic achievement are associated with economic growth and the promotion of positive educational outcomes for individual students. We seek to develop this idea and contribute to the income inequality literature by addressing the following hypotheses:
- Country-level income inequality is associated with average country-level academic achievement.
- Country-level income inequality is associated with student-level academic achievement.
- Country-level income inequality is associated with achievement gaps.
Methodology
We use data from the 2012 OECD Programme for International Student Assessment (PISA) and the OECD Statistics Database to draw conclusions about the relationship between national income inequality and educational outcomes. We include 41 high-income countries in our sample. PISA, our source of educational data, is a triennial international study that measures cross-national student achievement of 15-year old students in reading, math, and science.
The outcome variables for this study are math achievement measured at both the country and student levels. The national average math score represents the outcome measure for country-level achievement. This measure of country-level achievement is often used in media and academic reports to rank countries and compare levels of achievement. The students’ individual math scores represent the student-level achievement measure. The Gini coefficient, as collected from the OECD Statistics Database, represents country-level income inequality. The Gini coefficient signifies the actual distribution of income among households within a country compared to a perfect, equal income distribution.
We designed two models to measure the association of country-level income inequality on educational outcomes. The first model measures how country-level income inequality predicts country-level achievement, measured using the national average math score. This model uses OLS regression techniques for analysis to test our hypothesis that country-level income inequality is associated with average country-level income inequality. The second model examines how country-level income inequality predicts student-level achievement, measured by student-level math achievement scores. This model uses multilevel modeling to account for the nesting of students within schools and schools within countries. In these models, we also control for student background characteristics to improve the precision of our model estimates. Our hypothesis that country-level income inequality is associated with student-level academic achievement is measured in this model.
Results and Discussion
Our results suggest that national income inequality is negatively associated with both country-level and student-level achievement. Our first hypothesis, that country-level income inequality is associated with average country-level achievement is supported by our analyses. The regression coefficient of -1.91 means that the more unequal the country, the lower the overall math achievement. Thus, the increase of economic growth that is associated with increased country-level achievement can be further perpetuated with the decrease of country-level income inequality.
Our second hypothesis, that country-level income inequality is associated with student-level achievement is also supported by our analyses. The rate at which income inequality is associated with student achievement is small, but meaningful when extrapolated to large differences in income inequality. A one standard deviation increase in income inequality, as measured by the Gini coefficient, is associated with a 5.4 decrease in student scores. This means that countries that considerably deviate from average income inequality can experience a large decrease in student achievement scores. Our third hypothesis, that income inequality would have an effect on academic achievement gaps did not yield significant results. Thus, income inequality is not significantly related to SES-based achievement gaps in a nation.
Conclusion
While the relationship between national income inequality and educational outcomes are often assumed, this paper provides an empirical test of this relationship. Our results suggest that income inequality does matter when predicting educational outcomes; however, the effects of it are not as large as is commonly assumed. Large deviations from average income inequality, however, do result in large differences in academic achievement.
References
Beckfield, Jason. 2004. “Does Income Inequality Harm Health? New Cross-National Evidence.” Journal of Health and Social Behavior 45(3); 231-248.
Chiu, Ming Ming. 2007. “Families, economies, cultures, and science achievement in 41 countries: country-, school-, and student-level analyses.” Journal of Family Psychology 21(3): 510-519.
Duncan, Greg J. and Richard J. Murnane. 2014. “Growing income inequality threatens American education.” Phi Delta Kappan 95(6); 8-14.
Elgar, F. J., & Aitken, N. (2011). “Income inquality, trust, and homicide in 33 countries.” European Journal of Public Health 24(3), 241-246.
Navarro, V., Borrell, C., Benach, J., Muntaner, C., Quiroga, A., Rodriguez-Sanz, M.,et al. 2003. “The importance of the political and the social in explaining mortality differentials among the countries of the OECD, 1950-1998.” International Journal of Health Services 33, 419-494.
Smeeding, Timothy M. 2005. “Public Policy, Economic Inequality, and Poverty: the United States in Comaprative Perspective.” Social Science Quarterly 86; 955-983.