| model.matrix.selection {sampleSelection} | R Documentation |
Create design matrix of sample selection models
## S3 method for class 'selection': model.matrix(object, part = "outcome", ... )
object |
object of class selection. |
part |
character string indication which design matrix/matrices to extract: "outcome" for the design matrix/matrices of the outcome equation(s) or "selection" for the design matrix of the selection equation. |
... |
further arguments passed to other methods
(e.g. model.matrix.probit or model.matrix). |
If argument part is "selection",
the design matrix of the selection equation is returned.
If argument part is "outcome",
the design matrix of the outcome equation of a tobit-2 model
or a list that contains the design matrices of the (two) outcome equations
of a tobit-5 model is returned.
All values of observations (rows of the design matrix)
that were not selected for estimating the corresponding outcome equation
are set to NA.
Arne Henningsen
selection,
model.matrix, and model.matrix.probit