Sibling Set Order and Educational Attainment: Evidence from Fully Adopted Sibling Groups

Kieron Barclay, Stockholm University

There is an extensive literature concerning the relationship between birth order and educational attainment. Most explanations for the observation that later born children have lower educational attainment emphasise intrafamily social dynamics, but these differences may also have biological underpinnings. This study uses Swedish administrative register data to construct full sibling data for cohorts born 1960 to 1977 for fully adopted siblings sets. Using a within-family comparison approach, I study whether set order amongst adopted children is associated with differences in educational attainment by age 30. Analyses are also performed on siblings in fully biologically related sibling sets. I find that there is a negative relationship between set order and educational attainment in fully adopted sibling sets, which is slightly stronger than that seen in fully biologically related sibling sets. These findings strongly suggest that differences in educational attainment by set order are driven by intrafamily social dynamics.