plm (version 1.5-12)

pFormula: pFormula: An extended Formula interface for panel data

Description

pFormula is a Formula object, with methods useful for panel data.

Usage

pFormula(object)
"as.Formula"(x, ...)
"model.frame"(formula, data, ..., lhs = NULL, rhs = NULL)
"model.matrix"(object, data, model = c("pooling","within","Between", "between","mean","random","fd"),  effect = c("individual","time","twoways"), rhs = 1, theta = NULL, ...)

Arguments

object, formula, x

an object of class "pFormula",

data

a data.frame,

effect

the effects introduced in the model, one of "individual", "time" or "twoways",

model

one of "pooling", "within", "between", "random", "fd" and "ht",

theta

the parameter for the transformation if model = "random",

lhs

,

rhs

,

...

further arguments.

Value

An object of class c("pFormula", "Formula".

Details

The lhs and rhs arguments are inherited from Formula. The model.frame method returns a pdata.frame object. The model.matrix unables the transformation specified by the model and effect arguments.