micEcon (version 0.6-12)

translogCheckMono: Monotonicity of a Translog Function

Description

Check monotonicity of a translog function.

Usage

translogCheckMono( xNames, data, coef, increasing = TRUE, strict = FALSE, dataLogged = FALSE, tol = 10 * .Machine$double.eps )
"print"( x, ... )
"summary"( object, ... )
"print"( x, ... )

Arguments

xNames

a vector of strings containing the names of the independent variables.

data

dataframe containing the data.

coef

vector containing all coefficients.

increasing

single logical value or vector of logical values of the same length as argument xNames indicating whether it should be checked if the translog function is monotonically increasing (default, TRUE) or decreasing (FALSE) in the explanatory variables.

strict

logical. Check for strict (TRUE) or non-strict (default, FALSE) monotonicity?

dataLogged

logical. Are the values in data already logged?

tol

tolerance level for checking non-strict monotonicity: values between -tol and tol are considered to be zero (ignored if argument strict is TRUE).

x

an object returned by translogCheckMono or by summary.translogCheckMono.

object

an object returned by translogCheckMono.

...

currently not used.

Value

translogCheckMono returns a list of class translogCheckMono containing following objects:

obs

a vector indicating whether monotonicity is fulfilled at each observation.

exog

data frame indicating whether monotonicity is fulfilled for each exogenous variable at each observation.

increasing

argument increasing.

strict

argument strict.

Details

Function translogCheckMono internally calls function translogDeriv and then checks if the derivatives have the sign specified in argument increasing.

Function translogCheckMono does not have an argument shifterNames, because shifter variables do not affect the monotonicity conditions of the eplanatory variables defined in Argument xNames. Therefore, translogCheckMono automatically removes all coefficients of the shifter variables before it calls translogDeriv.

See Also

translogEst, translogDeriv, and translogCheckCurvature

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 )

   # check whether the production function is monotonically increasing
   # in all inputs
   test <- translogCheckMono( xNames = c( "qLabor", "land", "qVarInput", "time" ),
      data = germanFarms, coef = coef( estResult ) )
   test
   summary( test )

   # check whether the production function is monotonically decreasing
   # in time and monotonically increasing in all other inputs
   test <- translogCheckMono( c( "qLabor", "land", "qVarInput", "time" ),
      germanFarms, coef( estResult ), increasing = c( TRUE, TRUE, TRUE, FALSE ) )
   test
   summary( test )