micEcon (version 0.6-12)

translogCheckCurvature: Curvature of a Translog Function

Description

Check curvature of a translog function.

Usage

translogCheckCurvature( xNames, data, coef, convexity = TRUE, quasi = FALSE, dataLogged = FALSE, ... )
"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.

convexity

logical. Check whether the function is (quasi)convex (default, TRUE) or (quasi)concave (FALSE).

quasi

logical. Check whether the function is quasiconvex/quasiconcave (TRUE) or convex/concave (default, FALSE).

dataLogged

logical. Are the values in data already logged?

x

an object returned by translogCheckCurvature.

...

arguments passed from translogCheckCurvature to semidefiniteness (if argument quasi is FALSE), quasiconvexity (if arguments convexity and quasi are both TRUE), or quasiconcavity (if argument convexity is FALSE and quasi is TRUE). Further arguments to print.translogCheckCurvature are currently ignored.

Value

translogCheckCurvature returns a list of class translogCheckCurvature containing following objects:

obs

a vector indicating whether the condition for the specified curvature is fulfilled at each observation.

convexity

argument convexity.

quasi

argument quasi.

See Also

translogEst and translogCheckMono

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 quasiconcave
   translogCheckCurvature( c( "qLabor", "land", "qVarInput", "time" ),
      germanFarms, coef( estResult ), convexity = FALSE, quasi = TRUE )