Re: [R] Longitudinal categorical response data

2012-10-23 Thread Frank Harrell
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 ordi

Re: [R] Longitudinal categorical response data

2011-03-26 Thread Rune Haubo
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" : > > Dear List, > >

Re: [R] Longitudinal categorical response data

2011-03-24 Thread Ingmar Visser
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 wrote: > Dear List, > > I have some longitudinal data, each patient was followed at times

[R] Longitudinal categorical response data

2011-03-24 Thread Rasanga Ruwanthi
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