np (version 0.60-17)

Engel95: 1995 British Family Expenditure Survey

Description

British cross-section data consisting of a random sample taken from the British Family Expenditure Survey for 1995. The households consist of married couples with an employed head-of-household between the ages of 25 and 55 years. There are 1655 household-level observations in total.

Usage

data("Engel95")

Format

A data frame with 10 columns, and 1655 rows.

food

expenditure share on food, of type numeric

catering

expenditure share on catering, of type numeric

alcohol

expenditure share on alcohol, of type numeric

fuel

expenditure share on fuel, of type numeric

motor

expenditure share on motor, of type numeric

fares

expenditure share on fares, of type numeric

leisure

expenditure share on leisure, of type numeric

logexp

logarithm of total expenditure, of type numeric

logwages

logarithm of total earnings, of type numeric

nkids

number of children, of type numeric

References

Blundell, R. and X. Chen and D. Kristensen (2007), “Semi-Nonparametric IV Estimation of Shape-Invariant Engel Curves,” Econometrica, 75, 1613-1669.

Li, Q. and J.S. Racine (2007), Nonparametric Econometrics: Theory and Practice, Princeton University Press.

Examples

if (FALSE) {
## Example - compute nonparametric instrumental regression using
## Landweber-Fridman iteration of Fredholm integral equations of the
## first kind.

## We consider an equation with an endogenous regressor (`z') and an
## instrument (`w'). Let y = phi(z) + u where phi(z) is the function of
## interest. Here E(u|z) is not zero hence the conditional mean E(y|z)
## does not coincide with the function of interest, but if there exists
## an instrument w such that E(u|w) = 0, then we can recover the
## function of interest by solving an ill-posed inverse problem.

data(Engel95)

## Sort on logexp (the endogenous regressor) for plotting purposes

Engel95 <- Engel95[order(Engel95$logexp),] 

attach(Engel95)

model.iv <- npregiv(y=food,z=logexp,w=logwages,method="Landweber-Fridman")
phihat <- model.iv$phi

## Compute the non-IV regression (i.e. regress y on z)

ghat <- npreg(food~logexp,regtype="ll")

## For the plots, restrict focal attention to the bulk of the data
## (i.e. for the plotting area trim out 1/4 of one percent from each
## tail of y and z)

trim <- 0.0025

plot(logexp,food,
     ylab="Food Budget Share",
     xlab="log(Total Expenditure)",
     xlim=quantile(logexp,c(trim,1-trim)),
     ylim=quantile(food,c(trim,1-trim)),
     main="Nonparametric Instrumental Kernel Regression",
     type="p",
     cex=.5,
     col="lightgrey")

lines(logexp,phihat,col="blue",lwd=2,lty=2)

lines(logexp,fitted(ghat),col="red",lwd=2,lty=4)

legend(quantile(logexp,trim),quantile(food,1-trim),
       c(expression(paste("Nonparametric IV: ",hat(varphi)(logexp))),
         "Nonparametric Regression: E(food | logexp)"),
       lty=c(2,4),
       col=c("blue","red"),
       lwd=c(2,2))
}