Research on Inequality

Solt, Frederick. 2020. “Measuring Income Inequality Across Countries and Over Time: The Standardized World Income Inequality Database.” Social Science Quarterly 101(3):1183-1199. SWIID Version 9.0, October 2020.. (Pre-print available here; replication materials and revision history available here. For the SWIID itself, see here.) Objective: This article documents wide-ranging revisions to the Standardized World Income Inequality Database (SWIID), which seeks to maximize the comparability of income inequality estimates for the broadest possible coverage of countries and years. Methods: Two k-fold cross-validations, by observation and by country, are used to evaluate the SWIID’s success in predicting the Luxembourg Income Study (LIS), recognized in the field as setting the standard for comparability. Results: The cross-validations indicate that the new SWIID’s estimates and their uncertainty are even more accurate than previous versions, extending its advantage in comparability over alternate income inequality datasets. Conclusion: Given its superior coverage and comparability, the SWIID remains the optimum source of data for broadly cross-national research on income inequality.

Ritter, Michael, and Frederick Solt. 2019. ‘‘Economic Inequality and Campaign Participation.’’ Social Science Quarterly 100(3):678-688. (Pre-print available here; replication materials and revision history available here. Appendices.)
Objective. How does economic inequality shape participation in political campaigns? Previous research has found that higher inequality makes people of all incomes less likely to participate in politics, consistent with relative power theory, which holds that greater inequality enables wealthier citizens to more fully reshape the political landscape to their own advantage. Campaign activities, however, demand more time and money than previously examined forms of participation and so might better conform to the predictions of resource theory, which focuses narrowly on the ramifications of inequality for individuals’ resources. Methods. We combine individual-level data on donations, meeting attendance, and volunteer work for political campaigns with measures of state-level income inequality to construct a series of multilevel models. Results. The analyses reveal that where inequality is higher, campaign participation is lower among individuals of all incomes. Conclusions. Patterns of participation in even resource-intensive campaign activities provide support for the relative power theory.

Solt, Frederick, Yue Hu, Kevan Hudson, Jungmin Song, and Dong ‘Erico’ Yu. 2017. ‘‘Economic Inequality and Class Consciousness.’’ Journal of Politics 79(3):1079-1083. (Pre-print available here; replication materials and complete revision history available here.)
Do contexts of greater income inequality spur the disadvantaged to achieve a class consciousness vital to contesting the fairness of the economic system and demanding more redistribution? One prominent recent study, Newman, Johnston, and Lown (2015), argues that simple exposure to higher levels of local income inequality lead low-income people to view the United States as divided into haves and have-nots and to see themselves as among the have-nots, that is, to become more likely to achieve such a class consciousness. Here, we show that this sanguine conclusion is at best supported only in analyses of the single survey presented in that study. There is no evidence that higher levels of income inequality produce greater class consciousness among those with low incomes in other similar but neglected surveys.

Solt, Frederick, Yue Hu, Kevan Hudson, Jungmin Song, and Dong ‘Erico’ Yu. 2016. ‘‘Economic Inequality and Belief in Meritocracy in the United States.’’ Research & Politics 3(4):1-7. (Replication files available here; complete revision history available here. Appendix.)
How does the context of income inequality in which people live affect their belief in meritocracy, the ability to get ahead through hard work? A prominent recent study by Newman, Johnston, and Lown argues that, consistent with the conflict theory, exposure to higher levels of local income inequality leads lower-income people to become more likely to reject—and higher-income people to become more likely to accept—the dominant United States ideology of meritocracy. Here, we show that this conclusion is not supported by the study’s own reported results and that even these results depend on pooling three distinctly different measures of meritocracy into a single analysis. We then demonstrate that analysis of a larger and more representative survey employing a single consistent measure of the dependent variable yields the opposite conclusion. Consistent with the relative power theory, among those with lower incomes, local contexts of greater inequality are associated with more widespread belief that people can get ahead if they are willing to work hard.

Solt, Frederick. 2016. “The Standardized World Income Inequality Database.” Social Science Quarterly. 97(5):1267-1281. (Pre-publication copy available here; all materials needed to replicate the article are available here. The SWIID and materials to replicate it are available here.)
Objective. Investigating the causes and consequences of income inequality requires comparable data, but greater cross-national and temporal coverage is generally available only with sharply reduced comparability. The Standardized World Income Inequality Database (SWIID) provide researchers with data that maximize comparability for the broadest possible sample of countries and years. Methods. The SWIID employs a custom missing-data algorithm that minimizes reliance on problematic assumptions by using as much information as possible from proximate years within the same country to estimate inequality statistics for the missing country-years in the Luxembourg Income Study using data drawn from regional collections, national statistical offices, and academic studies. Results. The SWIID provides comparable estimates of the Gini index of net- and market-income inequality for 174 countries for as many years as possible from 1960 to the present, as well as measures of absolute and relative redistribution. Conclusions. As its coverage and comparability far exceed those of alternate datasets, the SWIID is better suited for broadly cross-national research on income inequality than other sources.

Solt, Frederick. 2015. “On the Assessment and Use of Cross-National Income Inequality Datasets.” Journal of Economic Inequality. 13(4):683-691. (Final pre-publication copy available here; replication files available here.)
Researchers should ensure the data they employ are fit for their purpose, and they should maximize the quality of the data they choose. In this paper, I review how this advice applies to broadly cross-national research on income inequality. I demonstrate that the guidance offered in Jenkins (2015) to those pursuing cross-national research runs completely counter to the recommendations found in Atkinson and Brandolini (2001, 2009), the source of the aforementioned advice and the works upon which Jenkins (2015) claims its own is based. I then show how the Standardized World Income Inequality Database (SWIID) incorporates Atkinson and Brandolini’s recommendations to provide the most comparable data available for those engaged in broadly cross-national research on income inequality.

Solt, Frederick. 2015. “Economic Inequality and Nonviolent Protest.” Social Science Quarterly 96(5):1314-1327. (Final pre-publication copy available here; replication files available here.)
Objective. Despite substantial theorizing, the relationship between economic inequality and participation in nonviolent protests has not been satisfactorily examined empirically. Methods. Using multilevel models of data from four waves of the European Social Survey, this article examines whether differences in inequality across countries and over time help explain people’s engagement in peaceful protest. Results. It finds that greater inequality reduces protest participation for all those with incomes below the top quintile. Conclusions. This result provides strong support for the relative power theory of political participation; the predictions of grievance and resource theories regarding inequality’s effects on protest are not supported.

Solt, Frederick. 2014. “Reversing the Arrow? Economic Inequality’s Effect on Religiosity.” In Religion and Inequality in America: Research and Theory on Religion’s Role in Stratification, L. Keister and D. Sherkat, eds., Cambridge: Cambridge University Press. (Final pre-publication copy available here; replication files available here.)
As other contributions to this volume document, there is considerable evidence that religious beliefs and practices shape stratification processes, working to maintain and perhaps even increase economic inequality. But what effect does the extent of inequality within a society have on the religiosity of the people who live there? In this chapter, I present time-series cross-sectional analyses of reported attendance at religious services in more than thirty countries over the past half century. These analyses indicate that rising levels of income inequality are soon followed by rising levels of religiosity. These results support relative power theory, which maintains that greater inequality yields more religiosity by increasing the degree to which wealthy people are attracted to religion and have the power to shape the attitudes and beliefs of those with fewer means.

Solt, Frederick. 2012. “The Social Origins of Authoritarianism.” Political Research Quarterly 65(4):703-713. (Replication files available here.)
Despite much attention to the problematic consequences of authoritarianism, little research focuses on the causes of such unquestioning respect for ‘proper’ authority. Elaborating on the social learning approach to authoritarianism, this paper argues that economic inequality within countries shapes individuals’ feelings towards authority. As differences in condition among members of a society increase, so does the relative power of the wealthy. As a result, regardless of their incomes, individuals’ experiences are more likely to lead them to view hierarchical relations as natural and, in turn, to hold greater respect for authority. Multilevel models of authoritarianism in countries around the world over three decades support this relative power theory.

Solt, Frederick. 2011. “Diversionary Nationalism: Economic Inequality and the Formation of National Pride.” Journal of Politics 73(3):821-830. (Replication files available here.)
What accounts for differences in the extent of nationalist sentiments across countries and over time? One prominent argument is that greater economic inequality prompts states to generate more nationalism as a diversion that discourages their citizens from recognizing economic inequality and mobilizing against it. Several other theories, however, propose different relationships between economic inequality and nationalism. This article provides a first empirical test of whether and how economic inequality is related to nationalism. Multilevel analyses using survey data on nationalist sentiments in countries around the world over a quarter century and data on economic inequality from the Standardized World Income Inequality Database provide powerful support for the diversionary theory of nationalism. This finding is an important contribution to our understanding of nationalism as well as of the political consequences of economic inequality.

Solt, Frederick, Philip Habel, and J. Tobin Grant. 2011. “Economic Inequality, Relative Power, and Religiosity.” Social Science Quarterly 92(2):447-465. (Replication files available here.)
Objective. What effect does the extent of economic inequality within a country have on the religiosity of the people who live there? As inequality increases, does religion serve primarily as a source of comfort for the deprived and impoverished or as a tool of social control for the rich and powerful? Methods. This article examine these questions with two complementary analyses of inequality and religiosity: a multilevel analysis of countries around the world over two decades and a time-series analysis of the United States over a half-century. Results. Economic inequality has a strong positive effect on the religiosity of all members of a society regardless of income. Conclusions. These results support relative power theory, which maintains that greater inequality yields more religiosity by increasing the degree to which wealthy people are attracted to religion and have the power to shape the attitudes and beliefs of those with fewer means.

Solt, Frederick. 2010. “Does Economic Inequality Depress Electoral Participation? Testing the Schattschneider Hypothesis.” Political Behavior 32(2):285-301. (Replication files available here.)
Nearly a half-century ago, E.E. Schattschneider wrote that the high abstention and large differences between the rates of electoral participation of richer and poorer citizens found in the United States were caused by high levels of economic inequality. Despite increasing inequality and stagnant or declining voting rates since then, Schattschneider’s hypothesis remains largely untested. This article takes advantage of the variation in inequality across states and over time to remedy this oversight. Using a multilevel analysis that combines aspects of state context with individual survey responses in 144 gubernatorial elections, it finds that citizens of states with greater income inequality are less likely to vote and that income inequality increases income bias in the electorate, lending empirical support to Schattschneider’s argument.

Solt, Frederick. 2009. “Standardizing the World Income Inequality Database.” Social Science Quarterly 90(2):231-242. (Final prepublication version available here.)
Objective. Cross-national research on the causes and consequences of income inequality has been hindered by the limitations of existing inequality datasets: greater coverage across countries and over time is available from these sources only at the cost of significantly reduced comparability across observations. The goal of the Standardized World Income Inequality Database (SWIID) is to overcome these limitations. Methods. A custom missing-data algorithm was used to standardize the United Nations University’s World Income Inequality Database; data collected by the Luxembourg Income Study served as the standard. Results. The SWIID provides comparable Gini indices of gross and net income inequality for 153 countries for as many years as possible from 1960 to the present along with estimates of uncertainty in these statistics. Conclusions. By maximizing comparability for the largest possible sample of countries and years, the SWIID is better suited to broadly cross-national research on income inequality than previously available sources.

Solt, Frederick.  2008.  “Economic Inequality and Democratic Political Engagement.” American Journal of Political Science 52(1):48-60.
What effect, if any, does the extent of economic inequality in a country have upon the political engagement of its citizens? This study examines this question using data from multiple cross-national surveys of the advanced industrial democracies. It tests the theory that greater inequality increases the relative power of the wealthy to shape politics in their own favor against rival arguments that focus on the effects of inequality on citizens' objective interests or the resources they have available for political engagement. The analysis demonstrates that higher levels of income inequality powerfully depress political interest, the frequency of political discussion, and participation in elections among all but the most affluent citizens, providing compelling evidence that greater economic inequality yields greater political inequality.

Solt, Frederick. 2004. “Civics or Structure? Revisiting the Origins of Democratic Quality in the Italian Regions.” British Journal of Political Science 34(1):123-135.
What determines the responsiveness and effectiveness of democratic governments in meeting their citizens’ needs?  Based on his 1993 study of the twenty Italian regions, Robert Putnam argued that ‘civic community,’ a self-reinforcing syndrome of social engagement and political participation, is the explanation.  A re-examination of Putnam’s data reveals little evidence of such a syndrome, but confirms that where more citizens participate in politics outside of networks of clientelistic exchange, more effective democratic government results.  To discern the causes of variation in this self-motivated political participation, I test Putnam’s measures of social engagement against aspects of Italian socio-economic structure.  Economic development and the historical distribution of land, not social engagement, are found to be powerful predictors of self-motivated political participation and in turn democratic quality.

Huber, Evelyne and Frederick Solt. 2004. “Successes and Failures of Neoliberalism in Latin America.” Latin American Research Review 39(3):150-164.
Much of the debate about the effects of neoliberal reforms in Latin America has been carried out at a political and ideological level: the image of an overblown and inefficient state that stifles market forces and private initiative has been contrasted with the model of a lean and efficient state that relies on the market to set free productive energies and thus stimulates growth and solves social problems. With this research note, we aim to make a contribution to the emerging empirically based scholarly literature that investigates the effects of neoliberal policy reforms. We find that, on average, in the Latin American countries neoliberal reforms have failed to put into place policies that firmly advance growth, stability, the reduction of poverty and inequality, and improvements of the human capital base.