Dear All, we (Ott Toomet and I) would like to add functions for maximum likelihood (ML) estimations of generalized tobit models of type 2 and type 5 (*see below) in my R package for microeconomic analysis "micEcon". So far we have called these functions "tobit2( )" and "tobit5( )". Are these classifications well known? How are these functions called in other software packages? Should we keep these names or does anybody have better suggestions?
(* T. Amemiya (1984): Tobit models: a survey, Journal of Econometrics, and T. Amemiya (1985): Advanced Econometrics) Furthermore, the generalized tobit model of type 2 is identical to the Heckman model. Until now the package "micEcon" contains a function "heckit( )" that performs a two-step estimation of the Heckman / Tobit type 2 model. The difference between "heckit( )" and "tobit2( )" is that "heckit( )" performs a two-step estimation, while "tobit2( )" performs a maximum likelihood estimation. At the moment we are debating how to construct the user interface. These are our suggestions: 1) Keep it as it is: heckit( ) does a two-step estimation and tobit2( ) does a ML estimation 2) Having just one function: tobit2( ..., method = "2step" ) does a two-step estimation tobit2( ..., method = "ML" ) does a ML estimation This has the advantage that other methods like a weighted two-step least squares can be added easily. 3) As suggestion 2). Argument "method" has the default "ML" and an additional a wrapper function is added: heckit <- function( ... ) { return( tobit2( ..., method = "2step" ) ) } Does anybody have a better suggestion? How is this implemented in other software packages? What do you think is the best option? Thanks, Arne Henningsen Ott Toomet -- Arne Henningsen Department of Agricultural Economics University of Kiel Olshausenstr. 40 D-24098 Kiel (Germany) Tel: +49-431-880 4445 Fax: +49-431-880 1397 [EMAIL PROTECTED] http://www.uni-kiel.de/agrarpol/ahenningsen/ ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html