translogCheckCurvature function

Curvature of a Translog Function

Check curvature of a translog function.

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

## S3 method for class 'translogCheckCurvature'
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.

Returns

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

Author(s)

Arne Henningsen

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 )