Sibling designs are an important analytical strategy to capture the family environment as a global measure, providing a summary indicator of all measured and unmeasured characteristics shared by siblings at birth and during their upbringing, such as genes, social environment, siblings interactions and many others. This, in turn, allows us to assess the relative importance of shared family characteristics vs. individual characteristics and of different parental background measures within the total family shared environment. This paper will provide new and robust empirical evidence regarding social inequalities in HE graduation. Using new siblings’ data from the Scottish Longitudinal Study (SLS), the paper addresses the following research questions:
(1) What is the share of between and within family variance in siblings’ HE outcomes?
(2) Does this differ by social class of origin and by other family characteristics?
(3) How much of the total variance between families is explained by parental social class, education and other family-level characteristics?
(4) What are the individual-level factors that explain the differences between siblings in the same family?
Types of inequalities
Sources of inequalities: People from more or less socially advantaged families are identified through measures of parental social class, parental education and housing tenure collected in 1991 when siblings were living in the parental home.
Inequalities of outcomes: variation in the chances of acquiring a HE qualification.
Our sample (N=2150) consists of pairs of siblings among the SLS members who were aged between 25 and 50 at the 2011 Census and lived in the same household at the 1991 Census. Given the structure of our data, namely individuals i (Level 1) nested in sibling dyads/families j (Level 2), we modelled our outcome (i.e. probability of attaining higher education) using random intercept effects/multilevel models, both binary logistic and linear probability models (LPM). Based on the individual-level and family-level variances, we calculated the Intraclass Correlation Coefficient (ICC) to assess siblings’ similarity.
Our results show that about 40% of the variation in the chances of attaining a university degree is explained by family-level characteristics shared by siblings, with the remaining 60% being explained by individual-level factors. Parental social class, parental education and housing tenure explain about a third of the total family-level variance. We found marked differences by socio-economic background with siblings from more disadvantaged families having a far lower chance that both of them obtain a degree (7-8%) than siblings from more advantaged families (57%). When considering a broader definition of higher education (including sub-degree qualifications), the overall influence of the family of origin is weaker but stark differences remain between siblings from more and less advantaged social backgrounds. Moreover, in our data we find that the sibling similarity is larger among siblings from more advantaged backgrounds. A plausible explanation of these findings is that better off families are able to compensate for variation in the abilities of their children to ensure that they all acquire a high level of education, whereas families from poorer backgrounds are not able to pursue such a strategy (i.e. they are more likely to use a ‘specialization’ strategy). Further analyses will investigate the greater variation in the likelihood of acquiring a degree among siblings in less well-off families.
Reducing inequalities in educational attainment and access to higher education (HE) are key policy priorities in Scotland and beyond. Our study provides new evidence on the relative importance of individual and family factors on the acquisition of higher education qualification. It will question whether the growing importance for widening access to HE of sub-degree level programmes provided in Further Education Colleges in Scotland is enough to compensate for the socio-economic gap in HE. Moreover, it will stress the importance of policies which not only focus on schools/universities but also directly target families in need of support.
For more information about this research, please contact Professor Cristina Iannelli