We are approaching the first stable version (1.0) of the frontier package, which provides tools for microeconomic Stochastic Frontier Analysis (SFA). I have uploaded a kind of beta release (version 0.99) of this package to CRAN. The most important differences to version 0.9 affect the user interface. I have modified the package so that it is (hopefully) simpler to use and the functions are more similar to other R functions. Unfortunately, these changes make the new version NOT backward compatible. The most significant changes are reported below. A full ChangeLog is available in the log messages of the SVN repository on R-Forge. Feedback about this package is highly appreciated. Please report any bugs, suggestions, feature requests, comments, and questions in the forums and trackers on R-Forge.


CHANGES IN VERSION 0.99-0

* corrected and considerably improved documentation of function "fontier"

* changed order of arguments of function "frontier"

* removed arguments "crossSectionName" and "timePeriodName" from function "frontier": in case of cross-section data, these variables (information) are not needed, and in case of panel data, the information on the panel structure
has to be added to the data set by the function "plm.data" of the "plm" package

* argument "modelType" of function "frontier" must be "ECF" or "EEF" now

* replaced argument "funtionType" of function "frontier" by argument "ineffDecrease"

* renamed argument "eta" of function "frontier" as "timeEffect"

* split argument "mu" of function "frontier" into "truncNorm" and "zIntercept"

* increased default value of argument "maxit" of function "frontier" to 1000

* renamed argument "step1" of function "frontier" as "searchStep"

* renamed argument "tol2" of function "frontier" as "searchTol"

* replaced argument "indic" of function "frontier" by "searchScale"

* renamed argument "gridno" of function "frontier" as "gridSize"

* renamed argument "igrid2" of function "frontier" as "gridDouble"

* renamed argument "iprint" of function "frontier" as "printIter"

* removed arguments "qxNames" and "quadHalf" from function "frontier", because quadratic or translog frontiers can be estimated with function
"frontierQuad" now

* added "logLik" method for objects of class "frontier"

* added function "frontierQuad" for estimating quadratic and translog frontiers

* added function "frontierTranslogRay" for estimating stochastic ray translog frontier functions

* added the generic function "efficiencies" and corresponding methods for default objects and objects of class "frontier"

* added "elas" method for objects of class "frontierQuad"

* function frontier() and frontierQuad() return the (matched) call now

* the matrix of efficiency estimates returned by "frontier" has row names (cross section units) and possibly column names (time period) now