Protection through Proof of Age. Birth Registration and Child Labor in Early 20th Century USA.

A birth certificate establishes a child's legal identity and is the sole official proof of a child's age. However, quantitative estimates on the economic significance of birth registration are lacking. Birth registration laws were enacted by the majority of U.S. states in late 19th and early 20th centuries. Controlling for state of birth and cohort effects, the differential timing of birth registration laws across US states is used to identify whether birth registration changed the effectiveness of child labor legislation between 1910 and 1930. The incidence of child labor declined significantly in the early 20th century. The study finds that if a birth registration law had been enacted by the time a child was born, the effectiveness of minimum working age legislation in prohibiting under-aged employment more than doubled. This effect was stronger for children residing in non-agricultural areas.