Heckman {vcdExtra}

Labour Force Participation of Married Women 1967-1971

Description

1583 married women were surveyed over the years 1967-1971, recording whether or not they were employed in the labor force.

The data, originally from Heckman & Willis (1977) provide an example of modeling longitudinal categorical data, e.g., with markov chain models for dependence over time.

Usage

data(Heckman)

Format

A 5-dimensional 2^5 array resulting from cross-tabulating 5 binary variables for 1583 observations. The variable names and their levels are:

No	Name	Levels
1	e1971	"71Yes", "No"
2	e1970	"70Yes", "No"
3	e1969	"69Yes", "No"
4	e1968	"68Yes", "No"
5	e1967	"67Yes", "No"

Details

Lindsey (1993) fits an initial set of logistic regression models examining the dependence of employment in 1971 (e1971) on successive subsets of the previous years, e1970, e1969, ... e1967.

Alternatively, one can examine markov chain models of first-order (dependence on previous year), second-order (dependence on previous two years), etc.

Source

Lindsey, J. K. (1993). Models for Repeated Measurements Oxford, UK: Oxford University Press, p. 185.

References

Heckman, J.J. & Willis, R.J. (1977). "A beta-logistic model for the analysis of sequential labor force participation by married women." Journal of Political Economy, 85: 27-58

Examples

data(Heckman)

# independence model
mosaic(Heckman, shade=TRUE)
# same, as a loglm()
require(MASS)
(heckman.mod0 <- loglm(~ e1971+e1970+e1969+e1968+e1967, data=Heckman))
mosaic(heckman.mod0, main="Independence model")

# first-order markov chain: bad fit
(heckman.mod1 <- loglm(~ e1971*e1970 + e1970*e1969 +e1969*e1968 + e1968*e1967, data=Heckman))
mosaic(heckman.mod1, main="1st order markov chain model")

# second-order markov chain: bad fit
(heckman.mod2 <- loglm(~ e1971*e1970*e1969 + e1970*e1969*e1968 +e1969*e1968*e1967, data=Heckman))
mosaic(heckman.mod2, main="2nd order markov chain model")

# third-order markov chain: fits OK
(heckman.mod3 <- loglm(~ e1971*e1970*e1969*e1968 + e1970*e1969*e1968*e1967, data=Heckman))
mosaic(heckman.mod2, main="3rd order markov chain model")