Socio-economic, cultural, social, and cognitive aspects of family background and the biology competency of ninth-graders in Germany

•The impact of family background on student achievement is examined.•The analyses include socio-economic, cultural, social and cognitive factors.•Parents’ competency is the most significant predictor of children’s competencies.•Socio-economic status loses its impact when parents’ competencies are considered.

Students’ academic achievement is related to different family background factors such as socio-economic, cultural, social, and cognitive factors. Research on family background has mainly focused on socio-economic factors, often neglecting the significance of providing a cognitively activating home environment. As a supplement to a large-scale study assessing the competency of ninth-graders in Biology in Germany, 543 parents provided information on their socio-economic, cultural, and social background and worked on a domain-specific competency test. By means of hierarchical regression analyses, we established the separate and combined effects of the different background variables on students’ performance. Including all predictors simultaneously in a prediction model, only two—the number of books in home (β = .11) and the biology competency of parents (β = .26)—significantly predicted differences in their children’s competency in biology. Based on the results, we advocate a more comprehensive assessment of family background.