frontier

News

• News about the frontier project are available at the project's R-Forge site.

What is frontier?

• frontier is an extension package for the "language and environment for statistical computing and graphics" called R.
• frontier estimates stochastic frontier production and cost functions by maximum likelihood. Two specifications are available: the error components specification with time-varying efficiencies (Battese and Coelli, 1992) and a model specification in which the firm effects are directly influenced by a number of variables (Battese and Coelli, 1995).
• frontier includes an improved version of the Fortran source code of Tim Coelli's software FRONTIER 4.1 and hence, provides the same features as FRONTIER 4.1. A comprehensive documentation of FRONTIER 4.1 is available in the working paper: Coelli, T.J. (1996), A Guide to FRONTIER Version 4.1: A Computer Program for Stochastic Frontier Production and Cost Function Estimation, Working Paper No. 7/96, Centre for Efficiency and Productivity Analysis (CEPA), Department of Econometrics, University of New England, Armidale, Australia. This working paper is available as the file "Front41.pdf" that is included in the archive "FRONT41-xp1.zip", which is available at http://www.uq.edu.au/economics/cepa/frontier.php. Alternatively, the this file can be downloaded from https://absalon.ku.dk/eportfolios/97/entries/124/files/eRLBmNpiTgduh7KxfYdqVZoUQkQNmddw315zb386. This documentation of FRONTIER 4.1 is also helpful to users of the frontier package, because this package is based on the FRONTIER 4.1 software.
• Furthermore, frontier includes functions for:
  • writing input files for FRONTIER 4.1 (function "front41WriteInput")
  • reading output files of FRONTIER 4.1 (function "front41ReadOutput")

What are the differences between FRONTIER 4.1 and the R package frontier?

• FRONTIER 4.1 is a stand-alone software, while the R package frontier is an add-on package to the software R.
• FRONTIER 4.1 only runs under MS-Windows, while the R package frontier runs under all major operating systems.
• Running FRONTIER 4.1 requires the preparation of an instruction file and a data file and possibly the modification of a file with settings, while the R package frontier has a much simpler user interface.
• The coefficients and efficiencies estimated by the R package frontier are directly available for further calculations.
• The Fortran code in FRONTIER 4.1 includes two bugs that in specific circumstances can result in wrong estimates (see below), while these bugs have been fixed in the R package frontier.
• The Fortran code in the R package frontier has been optimised for numerical stability so that the estimates are numerically more stable.
• The user can control more details of the estimation procedure and the calculation of the efficiency estimates when using the R package frontier.
• The R package frontier can calculate the marginal effects of the "z variable" on the efficiency estimates when using the efficiency effects model of Battese and Coelli (1995).

Who has written frontier?

• Tim Coelli has written the Fortran source code, which is the main component of this package.
• Arne Henningsen has improved the Fortran code, included it into an R package, and has written the R interface.

Where can I get frontier?

• The released version is available on CRAN
  • You can download the source code, binaries for MacOS X and MS-Windows, and the reference manual from http://cran.r-project.org/web/packages/frontier/.
  • You can install the package by typing at the R prompt (if you have internet access):

     install.packages( "frontier" )

• The current development version is available on R-Forge
  • You can download the source code and binaries for MacOS X and MS-Windows from http://r-forge.r-project.org/R/?group_id=275.
  • You can install the package by typing at the R prompt (if you have internet access):

     install.packages( "frontier", repos="http://R-Forge.R-project.org" )

Under which license is frontier released?

• Under the GNU General Public License (GPL)

Where can I ask questions, report bugs, or suggest new features?

• Please use a forum or "tracker" at the project's R-Forge site.

Which two bugs are in FRONTIER 4.1 that are fixed in the R package "frontier"?

• In case of unbalanced panel data sets, FRONTIER 4.1 returns some arbitray numbers for the efficiency estimates of the unobserved observations.
• When estimating an "Error Components Frontier" (ECF) with unbalanced panel data sets, FRONTIER 4.1 uses arbitrary numbers for the derivatives of the log-likelihood function for the unobserved observations, which usually leads the optimisation solver into a wrong direction.