semsfa (version 1.1)

summary.semsfa: Summary for semsfa object

Description

Create and print summary results of a stochastic frontier model object returned by semsfa() with regard to the "CONDITIONAL EXPECTATION ESTIMATE" of the first step and to the "VARIANCE COMPONENTS ESTIMATE" of the compound error.

Usage

# S3 method for semsfa
summary(object, ...)

Value

summary.semsfa returns the summary of an object returned by semsfa() with few modifications if bootstrap is carried out:

b.t

\(t\)-statistic given the bootstrapped standard errors for \(\lambda\) and \(\sigma\) (b.se)

b.pv

\(p\)-values of the \(t\)-statistic

Arguments

object

an semsfa object returned by semsfa()

...

further arguments to the summary method are currently ignored

Author

Giancarlo Ferrara and Francesco Vidoli

Details

Please note that if bootstrap is carried out the \(t\)-statistic is not reliable for testing the statistical significance of \(\sigma\) and \(\lambda\), because these parameters are censored and cannot follow a \(t\)-distribution. We suggest to compare the BIC of the semiparametric estimated model with the base model.

See Also

semsfa, efficiencies.semsfa

Examples

#generate data
set.seed(0)
n<-200

x<- runif(n, 1, 2)
fy<- 2+30*x-5*x^2
v<- rnorm(n, 0, 1)
u<- abs(rnorm(n,0,2.5))
#production frontier
y <- fy + v - u

dati<-data.frame(y,x)

#first-step: gam, second-step: fan (default)
#without bootstrap
o<-semsfa(y~s(x),dati,sem.method="gam")
summary(o)

# ... with bootstrap
o<-semsfa(y~s(x),dati,sem.method="gam",n.boot=100)
summary(o)