Project 6

Within-Family Inequalities Between Siblings: Mechanisms, Outcomes and Relationships


To describe inequalities between children raised in the same family, to explain how such inequalities emerge, and to show how such inequalities are related to social relationships between family members.

Theoretical background

For decades, authors have emphasized resemblances among siblings and have used such correlations to assess the key role of parents and intergenerational reproduction. In contrast to this dominant view, we aim to shift the focus from similarities to differences among siblings. Children raised within the same family often vary considerably in their level of “success” on various stratification outcomes, such as in education, in labor market outcomes, and in health and wellbeing. In this project we ask how we can explain differences between siblings within families and whether larger inequalities are associated with worsened social relationships within the family. We also describe inequalities within families relative to inequalities in society at large. Starting from the notion of resource competition, which posits that children compete for their parents’ time, affection, and resources, we address three related sociological problems. First, we are interested in parent-child relationships and interactions to understand whether and why siblings obtain different levels of parental investments. We focus on gender, birth order, biological-versus-step-children, and initial talents, to see whether parental resources are diluted to children in a biased way, depending on children’s characteristics. Secondly, using internationally comparative data, we examine to what extent biased resource dilution differs between societies and changes across birth cohorts. Third, we study whether inequalities between siblings have repercussions for the relationships between adult siblings and between siblings and their parents.

Research design

This project will use national survey data from the OKiN (Ouders en Kinderen in Nederland), national panel data from the NKPS (Netherlands Kinship Panel Study), and the internationally comparative SHARE data (Survey of Health, Ageing and Retirement in Europe). Possibly also analyses are done on Dutch register data and new vignet studies.

  • Kalmijn, Matthijs & Van de Werfhorst, Herman G. (2016). Sibship Size and Gendered Resource Dilution in Different Societal Contexts. PLoS ONE 11(8): e0160953.
  • Steelman, L. C., Powell, B., Werum, R., & Scott, C. (2002). Reconsidering the Effects of Sibling Configuration: Recent Advances and Challenges. Annual Review of Sociology, 28, 243-269.
  • Suitor, J. J. et al. (2017). Role of Perceived Maternal Favoritism and Disfavoritism in Adult Children’s Psychological Well-Being. Journals of Gerontology Series B, 72(6), 1054-1066.
Project initiators

Matthijs Kalmijn (UvA), Herman van de Werfhorst (UvA)


University of Amsterdam

Note: There will be maximally two of the three UvA projects funded.