Checking 'help("lmer")' leads me also to 'help("lmer-class")', both

of which are helpful. Unfortunately, I know of no general "predict"

method that's available for an object of class 'lmer'. A preliminary

function of that nature is as follows:

predict.lmerBin <- function(object, X){

# object has class "lmer"

# X = model matrix with columns

# matching object at X

if(missing(X))

X <- object at X

#

b <- fixef(object)

X %*% b

}

## To use this, you need to know how to use

# 'preduct.glm'.

# Example using data(Contraception), discussed in

(mlmR <- vignette("MlmSoftRev")) # opens in Adobe Acrobat

# To open a script file companion to vignette("MlmSoftRev")

#edit(mlmR) # with Rgui

#Stangle(mlmR$file) # with ESS

fitBin <- lmer(use ~ urban+age+livch+(1|district),

Contraception, binomial)

predict.lmerBin(fitBin)

Does this answer your question?

Spencer Graves

p.s. If your example had been simple and self-contained, it would have

been to reply, because I could copy a few lines of R code from your

email into R, tested a few ideas, and craft a reply in a very few

minutes, if not seconds. Without that, crafting a sensible reply takes

more time, partly because it's less clear what you need to know to move

to the next step, and partly because after I guess what you are really

asking, I must next hunt for a suitable example.

T. Florian Jaeger wrote:

Hi,

I am using lmer (from the package lme4) to predict a binary response

variable (REL) from a bunch of fixed effects and two random effects

(Speaker_ID and NPhead_lemma):

fit <- lmer(REL ~

SPEAKER_GENDER +

log(SPEECHRATE) +

SQSPEECHRATE +

.....

+ (1|Speaker_ID) + (1|NPhead_lemma),

family="binomial",

data=data.lmer,

method="Laplace", model=T, x=T)

I would like to get classification accuracies for the derived model,

or even do some evaluation (cross-validation), but I cannot find a way

to get to the predicted values. As far as I can tell no predict method

has been implemented for lmer, right? I also was trying to figure out

whether lmer stores the predicted values somewhere (I read the

documentation and implementation summary,

/library/lme4/doc/Implementation.pdf).

Many thanks for your help and my apologies if I overlooked something

really simple.

Florian

--

T. Florian Jaeger

Ph.D. student

Linguistics Department,

P: +1 (650) 725 2323

F: +1 (650) 723 5666

U:

http://www.stanford.edu/~tiflo/______________________________________________

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