Fertility and Women's Labor Supply
Fertility.RdCross-section data from the 1980 US Census on married women aged 21–35 with two or more children.
Format
A data frame containing 254,654 (and 30,000, respectively) observations on 8 variables.
- morekids
factor. Does the mother have more than 2 children?
- gender1
factor indicating gender of first child.
- gender2
factor indicating gender of second child.
- age
age of mother at census.
- afam
factor. Is the mother African-American?
- hispanic
factor. Is the mother Hispanic?
- other
factor. Is the mother's ethnicity neither African-American nor Hispanic, nor Caucasian? (see below)
- work
number of weeks in which the mother worked in 1979.
Details
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.
References
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.
Examples
data("Fertility2")
## conflicts in ethnicity coding
ftable(xtabs(~ afam + hispanic + other, data = Fertility2))
#> other no yes
#> afam hispanic
#> no no 25389 811
#> yes 1308 894
#> yes no 1568 0
#> yes 30 0
## 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)
#>
#> Call:
#> lm(formula = mkids ~ samegender, data = Fertility2)
#>
#> Residuals:
#> Min 1Q Median 3Q Max
#> -0.4108 -0.4108 -0.3440 0.5892 0.6560
#>
#> Coefficients:
#> Estimate Std. Error t value Pr(>|t|)
#> (Intercept) 0.343979 0.003962 86.83 <2e-16 ***
#> samegenderTRUE 0.066820 0.005585 11.96 <2e-16 ***
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#>
#> Residual standard error: 0.4837 on 29998 degrees of freedom
#> Multiple R-squared: 0.004749, Adjusted R-squared: 0.004716
#> F-statistic: 143.1 on 1 and 29998 DF, p-value: < 2.2e-16
#>
fm2 <- lm(mkids ~ gender1 + gender2 + samegender + age + afam + hispanic + other, data = Fertility2)
summary(fm2)
#>
#> Call:
#> lm(formula = mkids ~ gender1 + gender2 + samegender + age + afam +
#> hispanic + other, data = Fertility2)
#>
#> Residuals:
#> Min 1Q Median 3Q Max
#> -0.7078 -0.3823 -0.3000 0.5715 0.8317
#>
#> Coefficients:
#> Estimate Std. Error t value Pr(>|t|)
#> (Intercept) -0.1645094 0.0255081 -6.449 1.14e-10 ***
#> gender1male -0.0056508 0.0055293 -1.022 0.3068
#> gender2male -0.0128023 0.0055300 -2.315 0.0206 *
#> samegenderTRUE 0.0683138 0.0055294 12.355 < 2e-16 ***
#> age 0.0164593 0.0008182 20.116 < 2e-16 ***
#> afamyes 0.0962535 0.0123360 7.803 6.26e-15 ***
#> hispanicyes 0.1481327 0.0116248 12.743 < 2e-16 ***
#> otheryes 0.0240816 0.0131694 1.829 0.0675 .
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#>
#> Residual standard error: 0.4786 on 29992 degrees of freedom
#> Multiple R-squared: 0.02573, Adjusted R-squared: 0.0255
#> F-statistic: 113.1 on 7 and 29992 DF, p-value: < 2.2e-16
#>
fm3 <- lm(mkids ~ gender1 + twoboys + twogirls + age + afam + hispanic + other, data = Fertility2)
summary(fm3)
#>
#> Call:
#> lm(formula = mkids ~ gender1 + twoboys + twogirls + age + afam +
#> hispanic + other, data = Fertility2)
#>
#> Residuals:
#> Min 1Q Median 3Q Max
#> -0.7078 -0.3823 -0.3000 0.5715 0.8317
#>
#> Coefficients:
#> Estimate Std. Error t value Pr(>|t|)
#> (Intercept) -0.1773117 0.0255629 -6.936 4.11e-12 ***
#> gender1male 0.0071515 0.0078416 0.912 0.3618
#> twoboysTRUE 0.0555115 0.0077023 7.207 5.85e-13 ***
#> twogirlsTRUE 0.0811161 0.0079363 10.221 < 2e-16 ***
#> age 0.0164593 0.0008182 20.116 < 2e-16 ***
#> afamyes 0.0962535 0.0123360 7.803 6.26e-15 ***
#> hispanicyes 0.1481327 0.0116248 12.743 < 2e-16 ***
#> otheryes 0.0240816 0.0131694 1.829 0.0675 .
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#>
#> Residual standard error: 0.4786 on 29992 degrees of freedom
#> Multiple R-squared: 0.02573, Adjusted R-squared: 0.0255
#> F-statistic: 113.1 on 7 and 29992 DF, p-value: < 2.2e-16
#>