Cross-section data from the 1980 US Census on married women aged 21–35 with two or more children.
A data frame containing 254,654 (and 30,000, respectively) observations on 8 variables.
factor. Does the mother have more than 2 children?
factor indicating gender of first child.
factor indicating gender of second child.
age of mother at census.
factor. Is the mother African-American?
factor. Is the mother Hispanic?
factor. Is the mother's ethnicity neither African-American nor Hispanic, nor Caucasian? (see below)
number of weeks in which the mother worked in 1979.
Fertility2 is a random subset of
Fertility with 30,000 observations.
There are conflicts in the ethnicity coding (see also examples). Hence, it was not possible to create a single factor and the original three indicator variables have been retained.
Not all variables from Angrist and Evans (1998) have been included.
Online complements to Stock and Watson (2007).
Angrist, J.D., and Evans, W.N. (1998). Children and Their Parents' Labor Supply: Evidence from Exogenous Variation in Family Size American Economic Review, 88, 450–477.
Stock, J.H. and Watson, M.W. (2007). Introduction to Econometrics, 2nd ed. Boston: Addison Wesley.
data("Fertility2") ## conflicts in ethnicity coding ftable(xtabs(~ afam + hispanic + other, data = Fertility2)) ## create convenience variables Fertility2$mkids <- with(Fertility2, as.numeric(morekids) - 1) Fertility2$samegender <- with(Fertility2, factor(gender1 == gender2)) Fertility2$twoboys <- with(Fertility2, factor(gender1 == "male" & gender2 == "male")) Fertility2$twogirls <- with(Fertility2, factor(gender1 == "female" & gender2 == "female")) ## similar to Angrist and Evans, p. 462 fm1 <- lm(mkids ~ samegender, data = Fertility2) summary(fm1) fm2 <- lm(mkids ~ gender1 + gender2 + samegender + age + afam + hispanic + other, data = Fertility2) summary(fm2) fm3 <- lm(mkids ~ gender1 + twoboys + twogirls + age + afam + hispanic + other, data = Fertility2) summary(fm3)