Sibling structure and educational achievement: How do the number of siblings, birth order, and birth spacing affect children’s vocabulary competences?

Abstract

Empirical evidence suggests that sibling structure influences children’s educational outcomes: While the negative effect of the number of siblings is quite consistent, there are mixed findings for birth order and birth spacing. According to the resource dilution hypothesis, differences between siblings occur because siblings have to share family resources. Having a larger number of siblings, being a later-born child as well as narrow age gaps between siblings can affect the parental resources available for each child, which may thus negatively affect educational outcome. To study the effects of sibling structure, we use longitudinal data from the BiKS-8-14 study at the end of elementary school, focusing on children’s vocabulary competences. Our results indicate an expected negative effect for increasing number of siblings particularly when children originate from families with a lower educational background. Regarding birth order, we also find differential effects by parents’ education, as only children from less educated families suffer from being a later-born child. No effects can be identified for children’s birth gaps in relation to younger siblings as soon as number of siblings is being considered, whereas longer spacing between a child and his/her older siblings is positively related to vocabulary competences. With respect to possible changes across time, sibling effects appear to be rather stable at the end of primary education.
 Zusammenfassung
 Empirische Befunde weisen auf einen Einfluss von Geschwisterstrukturen auf den Bildungserfolg von Kindern hin: Während der negative Einfluss der Geschwisteranzahl als unstrittig gilt, zeigen sich unterschiedliche Ergebnisse hinsichtlich Geburtenreihenfolge und Geburtenabstand. Nach der Resource-Dilution-Hypothese können Disparitäten im Bildungserfolg darauf zurückgeführt werden, dass Ressourcen bei bestimmten familialen Strukturen aufgeteilt werden müssen. Kinder mit einer größeren Geschwisteranzahl, später geborene Kinder sowie Geschwister mit kurzen Geburtenabständen können durch geringere zur Verfügung stehende Ressourcen im Bildungserwerb benachteiligt sein. Mithilfe der Längsschnittstudie BiKS-8-14 werden Geschwistereffekte bei Kindern am Ende der Grundschulzeit hinsichtlich ihrer Wortschatzkompetenzen untersucht. Die Ergebnisse deuten auf einen negativen Effekt größerer Geschwisteranzahl hin, insbesondere bei niedrigem familialen Bildungshintergrund. Mit Blick auf die Geburtenreihenfolge können Nachteile im Wortschatz lediglich für später geborene Kinder aus Familien mit niedrigen Bildungsniveaus festgestellt werden. Hingegen zeigen sich keine Effekte beim Geburtenabstand zu jüngeren Geschwistern, sobald die Anzahl der Geschwister berücksichtigt wird, während sich ein größerer Geburtenabstand zu einem älteren Geschwisterkind positiv auf den Wortschatz auswirkt. Weiterhin erweisen sich die Auswirkungen von Geschwisterstrukturen am Ende der Grundschulzeit als äußerst konstant.

Competition in the Family: Inequality between Siblings and the Intergenerational Transmission of Educational Advantage

“…The present study found a compensatory effect of a high social origin with respect to track attendance but not with respect to cognitive skills. The findings for cognitive skills are at odds with the results of Karwath et al (2015), who reported a concentration of the negative association between birth order and children's vocabulary skills in socioeconomically disadvantaged families but did not use family fixed-effects models. Barclay (2015b), who used family fixed-effects models and Swedish register data, found, however, in line with my results, no socioeconomic differences in the effect of birth order on intelligence.…”

“…Barclay (2015b) found, using family fixed-effects models and data on Sweden, no socioeconomic differences in the effect of birth order on intelligence among brothers. Contrary to that, Karwath et al (2015) found, using data on a small region in Germany and not employing family fixed-effects models, a negative association between a higher birth order and vocabulary skills for children from less educated families but not for children from highly educated families. With respect to educational attainment, previous research based on withinfamily variation found no differences in birth order effects by maternal education in Norway (Black et al 2005) or by parental occupational status and education in Germany (Härkönen 2014).…”

“…A number of studies found negative causal effects of a higher birth order on children's cognitive skills and educational outcomes (e.g., Barclay 2015aBarclay , 2015bBjerkedal et al 2007;Black, Devereux, and Salvanes 2005;Booth and Kee 2009;Kantarevic and Mechoulan 2006;Bjerkedal 2007, 2010). In line with these results, previous research also found negative associations between birth order and educational outcomes in Germany (Karwath, Relikowski, and Schmitt 2015;Schulze and Preisendörfer 2013;Stoye 2016). In addition, Härkönen (2014) and Stoye (2016) used family fixed-effects models to estimate birth order effects within families in Germany.…”

Family Structure and Child Educational Attainment in the Slums of Nairobi, Kenya

“…At the household level, many studies, mostly in sociology, have found that the number of siblings exerts a negative effect on each child's educational attainment, including grade completion and test scores (Conley & Glauber, 2005;Karwath, Relikowski, & Schmitt, 2014). In one extensive study across various samples, Blake (1989) finds the "dilution effect": more siblings dilute a child's allocation of parental resources.…”

Educational test scores among adolescents in three-generational households in 20 countries

“…Child's gender may also influence parental involvement (e.g., Lundberg, 2005;Raley & Bianchi, 2005). Older children are shown to receive higher educational scores than younger ones (e.g., Karwath et al, 2014) and children's age tends to influence also parental involvement (Waldfogel, 2006). When the number of siblings in household increases, the amount of time parents are able to invest in any particular child tends to decrease (e.g., Downey, 2001;Coleman, 1988).…”