mgcv bam() with grouped binomial data

Hello,

I'm trying to use the bam() function in the R mgcv package for a large set of grouped binary data. However, I have found that this function does not take data in the format of cbind(numerator, denominator) on the left hand side of the formula. As an example, consider the following

dat1<- data.frame(id=rep(1:6, each=3), num=rbinom(18, size=10, prob=0.8), den=rbinom(18, size=5, prob=0.5), x=rnorm(18))
m1.1<- gam(cbind(num, den) ~ x+s(id, bs="re"), data=dat1, family=binomial)
m2.1<- bam(cbind(num, den) ~x+ s(id, bs="re"), data=dat1, family=binomial)

Running the above results in

dat1<- data.frame(id=rep(1:6, each=3), num=rbinom(18, size=10, prob=0.8), den=rbinom(18, size=5, prob=0.5), x=rnorm(18))
m1.1<- gam(cbind(num, den) ~ x+s(id, bs="re"), data=dat1, family=binomial)
m2.1<- bam(cbind(num, den) ~x+ s(id, bs="re"), data=dat1, family=binomial)

Error in dev.resids(y, mu, weights) :
   argument mu must be a numeric vector of length 1 or length 36

Is this a known issue? If so, is there a way to handle it?

Thank you,

Casey


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