[R] Missing names in LMER and GLM

[Greg Snow]

The default way that R deals with categorical variables is to choose one level as the baseline and measure everything else as differences from the baseline.  Based on the information that you gave us, the reasonable explanation is that MNX is used as the baseline and is represented in the intercept and the other coefficients measure the offset from MNX.  If this is not what is happening, then we will need a minimal, self-contained, reproducible example.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of vickih
> Sent: Monday, February 01, 2010 12:27 PM
> To: r-help at r-project.org
> Subject: [R] Missing names in LMER and GLM
> 
> 
> I'm having trouble with 'lmer' and would really appreciate it if
> anybody
> could help.
> 
> I am trying to run generalized linear mixed effect model, and am using
> 'lmer', but some of the names inside the data do not show up in the
> summary
> after I compute the 'lmer'. As a close example of the data I have, the
> objects are
> 
> 
> Calls = MM, MB, MM, MM, MN, MNX, MNX, ...
>       -this is made up of MM, MB, MN and MNX
> passes = 3, 5, 1, 6, 3, 6, 3, ...
>       - this is made up of integer values, each corresponding to either
> MM,
> MB, MN or MNX as in Calls
> Night = 1, 4, 5, 2, 4, 1, ...
>      - this is made up of integers from 1 to 5, and is a random
> variable
> 
> The command I use is
> LMER1 <- lmer(passes ~ Calls + (1|Night), family=Poisson,
> data=importeddata)
> 
> 
> My problem is that when I then do 'summary(LMER1)' I get some missing
> values,
> for example, myfixed effects are:
> 
>    CallsMM       71.24     14.24    ...etc
>    CallsMB        ....        ....         ...
>    CallsMN       ...           ..          ..
>                                         (the dots ... mean that there
> is a
> number there)
> However, CallsMNX is not there!
> I have had the same problem with GLM as well.
> 
> 
> Does anyone know what the problem might be?
> I hope my post has been clear enough. Thanks in advance for your help.
> --
> View this message in context: http://n4.nabble.com/Missing-names-in-
> LMER-and-GLM-tp1459176p1459176.html
> Sent from the R help mailing list archive at Nabble.com.
> 
> ______________________________________________
> R-help at 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.