Family-Size Effects on Earnings – Definitions Matter

Number of siblings has previously been found to adversely affect earned income. However, we still lack understanding of whether nature or nurture drives this effect. We examine in detail the effects of having different kinds of siblings and find that the number of siblings one grew up with has a strong negative effect on earnings, while the total number of siblings as such has no significant effect. We also find that number of full-siblings has a strong effect irrespective of having grown up together. Hence, both nature and nurture play a role.<p>