summary.selection function

Summarizing Selection Estimations

Print or return a summary of a selection estimation.

## S3 method for class 'selection'
summary(object, ...)
   ## S3 method for class 'summary.selection'
print(x,
      digits = max(3, getOption("digits") - 3),
      part = "full", ...)

Arguments

• object: an object of class 'selection'.
• x: an object of class 'summary.selection'.
• part: character string: which parts of the summary to print: "full" for all the estimated parameters (probit selection, outcome estimates, correlation and residual variance), or "outcome" for the outcome results only.
• digits: numeric, (suggested) number of significant digits.
• ...: currently not used.

Details

The variance-covariance matrix of the two-step estimator is currently implemented only for tobit-2 (sample selection) models, but not for the tobit-5 (switching regression) model.

Returns

Summary methods return an object of class summary.selection. Print methods return the argument invisibly.

Author(s)

Arne Henningsen, Ott Toomet otoomet@ut.ee

See Also

summary, selection, and selection-methods.

Examples

## Wooldridge( 2003 ): example 17.5, page 590
data( Mroz87 )
wooldridge <- selection( lfp ~ nwifeinc + educ + exper + I( exper^2 ) +
   age + kids5 + kids618, log( wage ) ~ educ + exper + I( exper^2 ),
   data = Mroz87, method = "2step" )

# summary of the 1st step probit estimation (Example 17.1, p. 562f)
# and the 2nd step OLS regression (example 17.5, page 590)
summary( wooldridge )

# summary of the outcome equation only
print(summary(wooldridge), part="outcome")