[R] [FORGED] Error from lme4: "Error: (p <- ncol(X)) == ncol(Y) is not TRUE"

[Rolf Turner]

On 23/09/15 01:18, Rory Wilson wrote:

> Hello all, I am trying to run a random intercept model using lme4.
> The random effect is a factor of 29 possibilities, making a model
> with one random effect (one level). It is just a linear model. There
> are 713 observations. However, when trying to run the model I receive
> the error "Error: (p <- ncol(X)) == ncol(Y) is not TRUE", a search
> for which reveals somewhat surprisingly little. Has anyone seen this
> before? Note that if I simply change the random effect into a fixed
> effect and use lm, the model works perfectly.Thank you!

[Caveat:  I really find the syntax of lmer() incomprehensible, so my 
example below could be a load of dingos' kidneys.]

I think a reproducible example (as specified by the posting guide) is 
needed here.  When I do:

set.seed(42)
f <- factor(sample(1:29,713,TRUE))
x <- seq(0,1,length=713)
y <- rnorm(713)
require(lme4)
fit <- lmer(y ~ x + (1|f))

I get a reasonable (???) looking result and no error messages.

cheers,

Rolf Turner

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