Social mobility and equality of opportunity have been of long-standing interest for both economists and sociologists. More recently, these concepts also gained centrality in political debates and are increasingly proposed as principles of social justice by politicians of different orientations.
Typically, the meaning of equality of opportunity remains vague in the public discourse, and this may partly explain its popularity. In economics, the basis for the definition of equality of opportunity has therefore been the distinction between individual efforts and pre-determined circumstances (Roemer, 1998; Fleurbaey, 2008; Roemer and Trannoy, 2014). Several approaches to operationalize this distinction have been proposed and a rapid expansion in empirical studies has ensued (see reviews in Pignataro, 2011; Brunori, Ferreira, and Peragine, 2014).
The definition of social mobility is also far from unequivocal (Jäntti and Jenkins, 2014). Much of the economic analysis of the relationship between the social status of parents and children has focused on the statistical association between the income (or earnings) of an individual with that of his/her parents. This has led to the stylized fact that countries with greater income inequality tend to be countries in which a greater fraction of economic advantage and disadvantage is passed on across generations (Corak, 2013; Bjorklund and Jantti, 2009).
Sociological research on stratification, on the other hand, has mainly focused on the transition rates between social classes and/or occupational groupings. Remarkably, the majority of sociological studies appear to treat social mobility and equality of opportunity as largely overlapping concepts, with high mobility rates being understood as an indication of overall 'fairness' or 'openness' of societies (Swift 2004). Claims about the need to distinguish between social mobility and equality of opportunity (Marshall et al. 1997; Swift 2004) have received relatively little attention from social stratification researchers.
The distinction between equality of opportunity and social (economic) mobility may be of particular interest to economists and social stratification researchers engaging in cross-country comparative analysis. International comparisons of social mobility are often used to infer the role of different institutional contexts (e.g. educational systems, labor market regulations etc.) in leveling the economic playing field. However, while certainly relating to discussions of equality of opportunity, such comparisons are not directly informative about the distinction between circumstances (for which individuals should be compensated) and personal efforts (for which they should be held responsible). In fact, as pointed out by prominent scholars in both economics and sociology (Bowles and Gintis, 2002; Roemer, 2004; Jencks and Tach, 2006; Corak, 2013) intergenerational status correlations reveal little about the types of advantages and investments passed on across generations.
We propose a general framework in which the different definitions of social mobility and equality of opportunity can be embedded. We clarify the links between the two concepts and obtain comparable estimates of equality of opportunity and social mobility for a large number of countries. The resulting empirical evidence is organized in a publicly accessible database: the "World Equality of Opportunity Database". We expect our portal to help researchers achieve a greater appreciation of the wider set of opportunities individuals face in different countries. This, in turn, can help clarify the role of various institutional settings and facilitate the debate around the relative merit of alternative compensatory policy interventions.