Thanks, David, you are right. If I use continuous data such as 1, 2, ...6 to represent those 6 housing types, the model works with the lme function in R. The problem is, the relationship between the 6 housing types are not continuous, which we assume when we use 1,2,..6 to represent them. Harry
On Tue, Aug 4, 2009 at 5:47 PM, David Winsemius <dwinsem...@comcast.net>wrote: > > On Aug 4, 2009, at 7:48 PM, Hongwei Dong wrote: > > Yeah, I have a very large sample size, about 60,000 observations. >> Multicollinearity should not be a problem here. The weird thing is that >> SPSS >> can converge very quickly and gives out reasonable results. >> The only problem I can think of is that, my first level (random) variables >> are dummy variables: 6 housing types, and I used five dummies in model and >> one as the reference. I also tried to combine them into two groups and use >> only dummy at random level, but it does not work either. >> >> is there any one here has similar experience with the LME function in R? >> > > I have absolutely no experience with "LME" but I can predict with very high > probability that you would be getting more sensible result if you modeled > those housing types with a single factor variable rather than creating 6 > dummies. ((Would one generally not create a reference dummy?) > > ?factor > > -- > David. > > > >> Thanks. >> >> Harry >> >> >> >> On Tue, Aug 4, 2009 at 1:28 AM, ONKELINX, Thierry >> <thierry.onkel...@inbo.be>wrote: >> >> Dear Harry, >>> >>> Your model seems rather complex. Do you have enough data to support it? >>> Did you check for multicollinearity between the variables? >>> >>> HTH, >>> >>> Thierry >>> >>> >>> >>> ------------------------------------------------------------------------ >>> ---- >>> ir. Thierry Onkelinx >>> Instituut voor natuur- en bosonderzoek / Research Institute for Nature >>> and Forest >>> Cel biometrie, methodologie en kwaliteitszorg / Section biometrics, >>> methodology and quality assurance >>> Gaverstraat 4 >>> 9500 Geraardsbergen >>> Belgium >>> tel. + 32 54/436 185 >>> thierry.onkel...@inbo.be >>> www.inbo.be >>> >>> To call in the statistician after the experiment is done may be no more >>> than asking him to perform a post-mortem examination: he may be able to >>> say what the experiment died of. >>> ~ Sir Ronald Aylmer Fisher >>> >>> The plural of anecdote is not data. >>> ~ Roger Brinner >>> >>> The combination of some data and an aching desire for an answer does not >>> ensure that a reasonable answer can be extracted from a given body of >>> data. >>> ~ John Tukey >>> >>> -----Oorspronkelijk bericht----- >>> Van: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] >>> Namens Hongwei Dong >>> Verzonden: maandag 3 augustus 2009 19:45 >>> Aan: r-help@r-project.org >>> Onderwerp: Re: [R] lme funcion in R >>> >>> Thanks for the replies above. Here are my script and data structure: >>> library(nlme) >>> tlevel<-lme(fixed = LN_unitlandval ~ >>> MH_D+APT_D+ResOth_D+NonRes_D+Vacant_D+access_emp1+pct_vacant+transit_D+p >>> ark_dum,data=lusdrdata,random >>> = ~MH_D+APT_D+ResOth_D+NonRes_D+Vacant_D | TAZ) >>> >>> str: >>> >>> $ TAZ : int 100 100 100 100 100 100 100 100 100 100 ... >>> $ MH_D : num 0 0 0 0 0 0 0 0 0 0 ... >>> $ APT_D : num 0 0 0 0 0 0 0 0 0 0 ... $ ResOth_D : num 0 0 0 0 0 0 0 0 0 >>> 0 ... $ NonRes_D : num 0 0 0 0 0 0 0 0 0 1 ... >>> $ Vacant_D : num 1 1 1 0 0 1 1 1 1 0 ... >>> $ access_emp1 : num 45.8 45.8 45.8 45.8 45.8 ... >>> $ pct_vacant : num 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 0.8 ... $ >>> transit_D : >>> num 0 0 0 0 0 0 0 0 0 0 ... $ park_dum : num 0 0 0 0 0 0 0 0 0 0 ... >>> >>> >>> Thanks. >>> >>> Harry >>> >>> >>> >>> On Mon, Aug 3, 2009 at 10:36 AM, Jason Morgan <jwm-r-h...@skepsi.net> >>> wrote: >>> >>> On 2009.08.03 10:15:46, Hongwei Dong wrote: >>>> >>>>> Hi, R users, >>>>> I'm using the "lme" function in R to estimate a 2 level mixed >>>>> effects model, in which the size of the subject groups are >>>>> different. It turned >>>>> >>>> out >>>> >>>>> that It takes forever for R to converge. I also tried the same thing >>>>> >>>> >>> in >>>>> >>>> SPSS >>>> >>>>> and SPSS can give the results out within 20 minutes. Anyone can give >>>>> >>>> >>> me >>>>> >>>> some >>>> >>>>> advice on the lme function in R, especially why R does not converge? >>>>> >>>> Thanks. >>>> >>>>> >>>>> Harry >>>>> >>>> >>>> Hello Harry, >>>> >>>> As Chuck mentions, providing some more information on the model and >>>> the data you are using would be helpful. Also, be sure to compare the >>>> optimization methods used in SPSS to that used in R. You can change >>>> the optimization method in R if the default seems to be causing >>>> issues. See help(lmeControl) for numerous setting options. >>>> >>>> ~Jason >>>> >>>> -- >>>> Jason W. Morgan >>>> Graduate Student >>>> Department of Political Science >>>> *The Ohio State University* >>>> 154 North Oval Mall >>>> Columbus, Ohio 43210 >>>> >>>> >>>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> R-help@r-project.org mailing list >>> https://stat.ethz.ch/mailman/listinfo/r-help >>> PLEASE do read the posting guide >>> http://www.R-project.org/posting-guide.html >>> and provide commented, minimal, self-contained, reproducible code. >>> >>> Dit bericht en eventuele bijlagen geven enkel de visie van de schrijver >>> weer >>> en binden het INBO onder geen enkel beding, zolang dit bericht niet >>> bevestigd is >>> door een geldig ondertekend document. The views expressed in this >>> message >>> and any annex are purely those of the writer and may not be regarded as >>> stating >>> an official position of INBO, as long as the message is not confirmed by >>> a >>> duly >>> signed document. >>> >>> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > David Winsemius, MD > Heritage Laboratories > West Hartford, CT > > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
