translogDeriv {micEcon}R Documentation

Derivatives of a translog function

Description

Calculate the derivatives of a translog function.

Usage

translogDeriv( xNames, data, coef, coefCov = NULL,
   yName = NULL, quadHalf = TRUE, dataLogged = FALSE )

Arguments

xNames a vector of strings containing the names of the independent variables.
data dataframe containing the data.
coef vector containing all coefficients.
coefCov optional covariance matrix of the coefficients.
yName an optional string containing the name of the dependent variable. If it is NULL, the dependent variable is calculated from the independent variables and the coefficients.
quadHalf logical. Multiply the quadratic terms by one half?
dataLogged logical. Are the values in data already logged?

Value

a list of class translogDeriv containing following objects:

deriv data frame containing the derivatives.
variance data frame containing the variances of the derivatives (not implemented yet).
stdDev data frame containing the standard deviations of the derivatives (not implemented yet).

Author(s)

Arne Henningsen

See Also

translogEst, translogCalc nad translogHessian

Examples

   data( germanFarms )
   # output quantity:
   germanFarms$qOutput <- germanFarms$vOutput / germanFarms$pOutput
   # quantity of variable inputs
   germanFarms$qVarInput <- germanFarms$vVarInput / germanFarms$pVarInput
   # a time trend to account for technical progress:
   germanFarms$time <- c(1:20)

   # estimate a translog production function
   estResult <- translogEst( "qOutput", c( "qLabor", "land", "qVarInput", "time" ),
      germanFarms )

   # compute the marginal products of the inputs (with "fitted" Output)
   margProducts <- translogDeriv( c( "qLabor", "land", "qVarInput", "time" ),
      germanFarms, coef( estResult ), vcov( estResult ) )
   margProducts$deriv

   # compute the marginal products of the inputs (with observed Output)
   margProductsObs <- translogDeriv( c( "qLabor", "land", "qVarInput", "time" ),
      germanFarms, coef( estResult ), vcov( estResult ), "qOutput" )
   margProductsObs$deriv

[Package micEcon version 0.5-14 Index]