Dear List,
I have some longitudinal data, each patient was followed at times 0, 12, 16, 24
weeks and measure severity of a illness (0-worse, 1-same, 2-better). So,
longitudinal response is categorical. I was wondering whether lmer in R can fit
a model for this type of data. If so, how we code? Or any other function in R
that can fit this type of longitudinal data? Any suggestion would be greatly
appreciated.
Thanks
Ruwanthi
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package msm has some examples with this type of type, ie modeling disease state transitions in continuous time, using multi-state markov models. hth, Ingmar On Thu, Mar 24, 2011 at 6:22 PM, Rasanga Ruwanthi <ruwanthi_kdr@yahoo.com>wrote:> Dear List, > > I have some longitudinal data, each patient was followed at times 0, 12, > 16, 24 weeks and measure severity of a illness (0-worse, 1-same, 2-better). > So, longitudinal response is categorical. I was wondering whether lmer in R > can fit a model for this type of data. If so, how we code? Or any > other function in R that can fit this type of longitudinal data? Any > suggestion would be greatly appreciated. > > Thanks > Ruwanthi > > > > > [[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. > >[[alternative HTML version deleted]]
lmer is not designed for ordered categorical data as yours are. You could take a look at the ordinal package which is designed for this type of data including mixed models (function clmm) which you probably want to use. Best, Rune Den 24/03/2011 21.03 skrev "Rasanga Ruwanthi" <ruwanthi_kdr@yahoo.com>:> > Dear List, > > I have some longitudinal data, each patient was followed at times 0, 12,16, 24 weeks and measure severity of a illness (0-worse, 1-same, 2-better). So, longitudinal response is categorical. I was wondering whether lmer in R can fit a model for this type of data. If so, how we code? Or any other function in R that can fit this type of longitudinal data? Any suggestion would be greatly appreciated.> > Thanks > Ruwanthi > > > > > [[alternative HTML version deleted]] > > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code. >[[alternative HTML version deleted]]
Random effects models of the type fitted by ordinal assume something akin to compound symmetry, which is not realistic when time between measurements is long or irregular. Frank Rune Haubo-2 wrote> lmer is not designed for ordered categorical data as yours are. You could > take a look at the ordinal package which is designed for this type of data > including mixed models (function clmm) which you probably want to use. > > Best, > Rune > > Den 24/03/2011 21.03 skrev "Rasanga Ruwanthi" <> ruwanthi_kdr@> >: >> >> Dear List, >> >> I have some longitudinal data, each patient was followed at times 0, 12, > 16, 24 weeks and measure severity of a illness (0-worse, 1-same, > 2-better). > So, longitudinal response is categorical. I was wondering whether lmer in > R > can fit a model for this type of data. If so, how we code? Or any > other function in R that can fit this type of longitudinal data? Any > suggestion would be greatly appreciated. > >> >> Thanks >> Ruwanthi >> >> >> >> >> [[alternative HTML version deleted]] >> >> >> ______________________________________________ >>> R-help@> 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. >> > > [[alternative HTML version deleted]] > > ______________________________________________> R-help@> 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.----- Frank Harrell Department of Biostatistics, Vanderbilt University -- View this message in context: http://r.789695.n4.nabble.com/Longitudinal-categorical-response-data-tp3403619p4647190.html Sent from the R help mailing list archive at Nabble.com.