Description Usage Arguments Details Value Author(s) See Also Examples
View source: R/summary.frontier.R
Create and print summary results of a stochastic frontier analysis
returned by frontier
.
1 2 3 4 5 |
object |
an object of class |
x |
an object of class |
extraPar |
logical. If |
effic |
logical. Print the individual efficiency estimates? |
logDepVar |
logical. Is the dependent variable logged? |
effMinusU |
logical. If |
farrell |
logical. This argument is only kept for backward compatibility and will be removed in the future. |
... |
further arguments to the |
The standard errors of the estimated parameters are taken from the direction matrix that is used in the final iteration of the Davidon-Fletcher-Powell procedure that is used for maximising the (log) likelihood function.
If argument extraPar
is TRUE
,
the standard errors of the additional parameters
are obtained by the delta method.
Please note that the delta method might provide poor approximations
of the ‘true’ standard errors,
because parameter sigma^2 is left-censored
and parameter gamma is both left-censored and right-censored
so that these parameters cannot be normally distributed.
Please note further that the t statistic and the z statistic are not reliable for testing the statistical signicance of sigma^2, gamma, and the ‘additional parameters’, because these parameters are censored and cannot follow a normal distribution or a t distribution.
summary.frontier
returns a list of class summary.frontier
that is identical to an object returned by frontier
with two modifications and (up to) four additional elements:
olsParam |
matrix of OLS estimates, their standard errors, t-values, and P-values. |
mleParam |
matrix of ML estimates, their standard errors, z-values, and asymptotic P-values. |
logDepVar |
logical. Argument |
printEffic |
argument |
effic |
matrix. Efficiency estimates: each row corresponds to a cross-section; each column corresponds to a time period. |
efficMean |
numeric scalar. Mean efficiency. |
efficYearMeans |
numeric vector. Mean efficiency for each year in the sample (only for panel data but not for the Error Components Frontier without time effects). |
Arne Henningsen
sfa
, efficiencies.frontier
,
vcov.frontier
, and lrtest.frontier
.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | # example included in FRONTIER 4.1 (cross-section data)
data( front41Data )
sfaResult <- sfa( log( output ) ~ log( capital ) + log( labour ),
data = front41Data )
summary( sfaResult )
# rice producers in the Phillipines (panel data)
data( "riceProdPhil" )
library( "plm" )
riceProdPhil <- pdata.frame( riceProdPhil, c( "FMERCODE", "YEARDUM" ) )
# Error Components Frontier
rice <- sfa( log( PROD ) ~ log( AREA ) + log( LABOR ) + log( NPK ),
data = riceProdPhil )
summary( rice )
# Efficiency Effects Frontier
rice2 <- sfa( log( PROD ) ~ log( AREA ) + log( LABOR ) + log( NPK ) |
EDYRS + BANRAT, data = riceProdPhil )
summary( rice2 )
|
Loading required package: micEcon
If you have questions, suggestions, or comments regarding one of the 'micEcon' packages, please use a forum or 'tracker' at micEcon's R-Forge site:
https://r-forge.r-project.org/projects/micecon/
Loading required package: lmtest
Loading required package: zoo
Attaching package: 'zoo'
The following objects are masked from 'package:base':
as.Date, as.Date.numeric
Please cite the 'frontier' package as:
Tim Coelli and Arne Henningsen (2013). frontier: Stochastic Frontier Analysis. R package version 1.1. http://CRAN.R-Project.org/package=frontier.
If you have questions, suggestions, or comments regarding the 'frontier' package, please use a forum or 'tracker' at frontier's R-Forge site:
https://r-forge.r-project.org/projects/frontier/
Error Components Frontier (see Battese & Coelli 1992)
Inefficiency decreases the endogenous variable (as in a production function)
The dependent variable is logged
Iterative ML estimation terminated after 7 iterations:
log likelihood values and parameters of two successive iterations
are within the tolerance limit
final maximum likelihood estimates
Estimate Std. Error z value Pr(>|z|)
(Intercept) 0.561619 0.202617 2.7718 0.0055742 **
log(capital) 0.281102 0.047643 5.9001 3.632e-09 ***
log(labour) 0.536480 0.045252 11.8555 < 2.2e-16 ***
sigmaSq 0.217000 0.063909 3.3955 0.0006851 ***
gamma 0.797207 0.136424 5.8436 5.109e-09 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
log likelihood value: -17.02722
cross-sectional data
total number of observations = 60
mean efficiency: 0.7405678
Loading required package: Formula
Error Components Frontier (see Battese & Coelli 1992)
Inefficiency decreases the endogenous variable (as in a production function)
The dependent variable is logged
Iterative ML estimation terminated after 11 iterations:
log likelihood values and parameters of two successive iterations
are within the tolerance limit
final maximum likelihood estimates
Estimate Std. Error z value Pr(>|z|)
(Intercept) -0.832169 0.275249 -3.0233 0.0025 **
log(AREA) 0.453897 0.063801 7.1143 1.125e-12 ***
log(LABOR) 0.288924 0.063639 4.5400 5.625e-06 ***
log(NPK) 0.227544 0.040859 5.5690 2.562e-08 ***
sigmaSq 0.155377 0.024202 6.4201 1.362e-10 ***
gamma 0.464312 0.088023 5.2749 1.328e-07 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
log likelihood value: -86.43042
panel data
number of cross-sections = 43
number of time periods = 8
total number of observations = 344
thus there are 0 observations not in the panel
mean efficiency: 0.8187968
Efficiency Effects Frontier (see Battese & Coelli 1995)
Inefficiency decreases the endogenous variable (as in a production function)
The dependent variable is logged
Iterative ML estimation terminated after 47 iterations:
log likelihood values and parameters of two successive iterations
are within the tolerance limit
final maximum likelihood estimates
Estimate Std. Error z value Pr(>|z|)
(Intercept) -1.051760 0.252988 -4.1573 3.220e-05 ***
log(AREA) 0.379767 0.059976 6.3320 2.420e-10 ***
log(LABOR) 0.321029 0.061125 5.2520 1.504e-07 ***
log(NPK) 0.263797 0.034458 7.6555 1.925e-14 ***
Z_(Intercept) -2.746459 8.499182 -0.3231 0.7466
Z_EDYRS -0.028610 0.215997 -0.1325 0.8946
Z_BANRAT -3.635528 8.096562 -0.4490 0.6534
sigmaSq 1.666588 3.695869 0.4509 0.6520
gamma 0.978799 0.045203 21.6536 < 2.2e-16 ***
---
Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
log likelihood value: -77.31363
panel data
number of cross-sections = 43
number of time periods = 8
total number of observations = 344
thus there are 0 observations not in the panel
mean efficiency of each year
1 2 3 4 5 6 7 8
0.7619359 0.7505762 0.8311524 0.8118776 0.7641510 0.8081221 0.7049660 0.8466347
mean efficiency: 0.784927
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