[R] effect() error: non-conformable arguments

John Fox jfox at mcmaster.ca
Fri Feb 8 14:57:03 CET 2013

Dear Elisha,

It's impossible to tell from the information that you provide what the
source of the problem is. The gold standard for a problem report is
"commented, minimal, self-contained, reproducible code" (quoting from the
text at the bottom of all r-help postings) that would allow me to track down
the error, but you don't even show the model that you've fit. I suspect that
there's something about the model that's incompatible with the effect()
function but what that might be is impossible to know from your message.

Please provide some more details and ideally a reproducible example.


John Fox
Senator McMaster Professor of Social Statistics
Department of Sociology
McMaster University
Hamilton, Ontario, Canada

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
> On Behalf Of Elisha Sigmon
> Sent: Thursday, February 07, 2013 2:57 PM
> To: r-help at r-project.org
> Subject: [R] effect() error: non-conformable arguments
> I am trying to calculate adjusted means according to a glm model with a
> Poisson distribution using effect() in the 'effects' package. I've done
> this many times before with great success, but this time I'm getting an
> error. My model contains two factors and two covariates/blocks and I
> would
> like the adjusted mean and confidence intervals for each factor
> separately.
> The model runs without errors as does Anova() and HSD.test() on the
> model,
> but when I try to run effect("factor", model) I get the following error:
> Error in mod.matrix %*% V : non-conformable arguments
> I understand that this error indicates that matrices are being created
> with
> dimensions that can't be used in the calculations, or something to that
> effect. But I don't understand enough about how the effect() function is
> calculated to figure out where the problem is in my data. I checked my
> data
> file for any NAs, missing values, etc. and can't find any problems. If
> anyone has any suggestions for diagnostics or how to find the source of
> this error I would greatly appreciate the help.
> Thanks!
> --
> Elisha Sigmon
> Ph.D. Candidate
> The George Washington University
> Department Of Biological Sciences
> 2023 G St. NW Suite 340
> Washington, DC, USA 20052
> 	[[alternative HTML version deleted]]
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> PLEASE do read the posting guide http://www.R-project.org/posting-
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> and provide commented, minimal, self-contained, reproducible code.

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