Sibling Similarity in Income: A Life Course Perspective

The similarity in income among siblings is a measure of the omnibus effect of family and community background on income. We estimate sibling similarity in income taking a life course perspective. We employ high-quality Swedish register data that allow us not only to look at the variation in sibling similarity over the life course but also to estimate sibling resemblance in income accumulated over the whole life course. Our findings show that sibling similarity in accumulated income is higher than sibling similarity in income at any specific age. Sibling similarity in accumulated income is largely stable over the life course. It is lower for sisters than for brothers, but differences diminish across cohorts. We also find largely the same amount of sibling similarity in accumulated income in socioeconomically advantaged and in socioeconomically disadvantaged families. We conclude that previous research underestimated the intergenerational persistence of income by focusing on non-accumulated measures. Our study shows that intergenerational income mobility is lower than previously assumed, even in a society with universal, free education and low income inequality.