Number of siblings, family background, and the process of educational attainment

The effects of number of siblings on educational attainment were analyzed in probability samples of 57,000 white men in the US. Also addressed was the relative importance of sibship size compared with father's education, father's socioeconomic status, farm background, and a broken family. The data revealed a marked linear association between sibsize and total years of education. The difference between the extremes of sibsize was more than double the racial difference and 3 times the age difference. Sibsize operates not simply by diluting parental economic resources for postsecondary education, but by impinging on education at the graded level. Males from large versus small families lose an average of 1 year of graded schooling, which implies large differences in proportions graduating from high school. Sibsize influences college attendance much less than it influences graded schooling; at higher levels of education, IQ, performance, and motivation are more decisive factors. Whereas father's education and sibsize are the most important determinants of total years of education and years of graded schooling, college schooling is more dependent on the father's socioeconomic status than other family background variables.