cobbDouglasOpt {micEcon} | R Documentation |
Calculate the optimal values of the variable independent variables of a Cobb-Douglas function.
cobbDouglasOpt( pyName, pxNames, data, coef, zNames = NULL, zCoef = NULL, xNames = NULL, dataLogged = FALSE )
pyName |
character string containing the name of the price of the dependent variable. |
pxNames |
a vector of strings containing the names of the prices of the variable independent variables. |
data |
data frame containing the data. |
coef |
vector containing the intercept and the coefficients
of the variable independent variables:
if the elements of the vector have no names,
the first element is taken as intercept of the logged equation
and the following elements are taken as coefficients of
the variable independent variables with corresponding prices
defined in argument pxNames (in the same order);
if the elements of coef have names,
the element named a_0 is taken as intercept of the logged
equation
and the elements named a_1 , ..., a_n
are taken as coefficients of the variable independent variables
with corresponding prices
defined in argument xNames (numbered in that order). |
zNames |
optional vector of strings containing the names of the fixed independent variables. |
zCoef |
vector containing the coefficients
of the fixed independent variables:
if the elements of the vector have no names,
they are taken as coefficients of the fixed independent variables
defined in argument zNames (in the same order);
if the elements of coef have names,
the elements named d_1 , ..., d_m
are taken as coefficients of the fixed independent variables
with corresponding prices
defined in argument zNames (numbered in that order). |
xNames |
optional vector of strings containing the names that should be assigned to the returned variable independent variables. |
dataLogged |
logical. Are the prices and fixed independent variables
in data
with names defined in pyName , pxNames , and zNames
already logged? |
A data frame containing the optimal values of the variable
independent variables.
If the prices and fixed independent variables are provided
as logarithmic values
(argument dataLogged
is TRUE
),
the optimal values of the variable independent variables are returned
as logarithms, too;
non-logarithmic values are returned otherwise.
Arne Henningsen
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$time <- c(1:20) # estimate a Cobb-Douglas production function estResult <- translogEst( yName = "qOutput", xNames = c( "qLabor", "qVarInput", "land", "time" ), data = germanFarms, linear = TRUE ) # calculate optimal quantities of variable inputs xCoef <- coef( estResult )[ 1:3 ] zCoef <- coef( estResult )[ 4:5 ] names( zCoef ) <- c( "d_1", "d_2" ) optInput <- cobbDouglasOpt( pyName = "pOutput", pxNames = c( "pLabor", "pVarInput" ), coef = xCoef, data = germanFarms, xNames = c( "qLabor", "qVarInput" ), zNames = c( "land", "time" ), zCoef = zCoef ) # compare observed with optimal input quantities plot( germanFarms$qLabor, optInput$qLabor ) plot( germanFarms$qVarInput, optInput$qVarInput )