micEconDistRay (version 0.1-2)

distRayEst: Estimate a Ray-Based Input Distance Function

Description

Empirically analyse multiple-input-multiple-output production technologies by estimating a ray-based input distance function (Price & Henningsen, forthcoming).

Usage

distRayEst( xNames, yNames, zNames = NULL, sNames = NULL, 
  data, form = "tl", method = "sfa", fixThetas = FALSE, ... )

Value

A list that will be described here later.

Arguments

xNames

a vector of character strings containing the names of the variables that indicate the input quantities.

yNames

a vector of two or more character strings containing the names of the variables that indicate the output quantities.

zNames

an optional vector of character strings containing the names of ‘environmental’ variables, i.e., variables that affect the production possibility set (i.e., the feasible combinations of input-output quantities) that---in the case of a Translog functional form---should be interacted with the input quantities and the angles of the output vector.

sNames

an optional vector of character strings containing the names of ‘environmental’ variables, i.e., variables that affect the production possibility set (i.e., the feasible combinations of input-output quantities) that---in the case of a Translog functional form---should not be interacted with the input quantities and the angles of the output vector.

data

data frame containing the data.

form

a character string that indicates the functional form; currently, "cd" for the Cobb-Douglas functional form and "tl" for the Translog functional form are available.

method

a character string that indicates the estimation method; currently, "lm" for the Ordinary Least-Squares method (using the lm() function of the stats package) and "sfa" for stochastic frontier estimation (using the sfacross() function of the sfaR package) are available.

fixThetas

logical value that indicates whether undefined angles of the output should be ‘fixed’ if the last two or more output quantities are zero for some of the observations.

...

further arguments of distRayEst are passed to lm or sfacross.

Author

Arne Henningsen and Juan José Price

References

Price, J.J. & Henningsen, A. (forthcoming): A Ray-Based Input Distance Function to Model Zero-Valued Output Quantities: Derivation and an Empirical Application. Journal of Productivity Analysis.

Examples

# load and prepare data set 
data( appleProdFr86, package = "micEcon" )
appleProdFr86$qCap <- appleProdFr86$vCap / appleProdFr86$pCap
appleProdFr86$qLab <- appleProdFr86$vLab / appleProdFr86$pLab
appleProdFr86$qMat <- appleProdFr86$vMat / appleProdFr86$pMat

# Cobb-Douglas ray-based input distance function
estCD <- distRayEst( xNames = c( "qCap", "qLab", "qMat" ),
  yNames = c( "qApples", "qOtherOut" ),
  data = appleProdFr86, form = "cd" )
summary( estCD )

# Translog ray-based input distance function
estTL <- distRayEst( xNames = c( "qCap", "qLab", "qMat" ),
  yNames = c( "qApples", "qOtherOut" ),
  data = appleProdFr86 )
summary( estTL )