Description of Fertility Dataset

Source: Angrist, Joshua D., and William N. Evans. "Children and Their Parents' 
Labor Supply: Evidence from Exogenous Variation in Family Size." American 
Economic Review 88, no. 3 (1998): 450-477.

The dataset contains cross-sectional data from the 1980 U.S. Census Public Use 
Micro Sample (PUMS) on 254,654 married women aged 21-35 with two or more 
children. The data were used to study the effect of fertility on women's labor 
supply using the sex composition of the first two children as an instrumental 
variable.

Sample: Married women aged 21-35 with at least two children

Number of observations: 254,654

Variables:

morekids -- Binary indicator equal to 1 if the woman had more than two 
            children, 0 if exactly two children

boy1st -- Binary indicator equal to 1 if the first child was a boy, 0 if girl

boy2nd -- Binary indicator equal to 1 if the second child was a boy, 0 if girl

samesex -- Binary indicator equal to 1 if the first two children are the same 
           sex (both boys or both girls), 0 otherwise. This variable serves as 
           the instrumental variable in the analysis.

agem1 -- Age of the mother at the time of the census (in years)

black -- Binary indicator equal to 1 if the mother is Black, 0 otherwise

hispan -- Binary indicator equal to 1 if the mother is Hispanic, 0 otherwise

othrace -- Binary indicator equal to 1 if the mother is neither White, Black, 
           nor Hispanic, 0 otherwise

weeksm1 -- Number of weeks the mother worked in the year prior to the census

Note: The ethnicity variables (black, hispan, othrace) are mutually exclusive 
but do not include a separate indicator for White women, who form the reference 
category.