Robert Long - 8 months ago 95

R Question

I am using the

`twang`

`survey::svyglm`

`pscore <- ps(ppci ~ var1+var2+.........., data=dt....)`

dt$w <- get.weights(pscore, stop.method="es.mean")

design.ps <- svydesign(ids=~1, weights=~w, data=dt,)

glm1 <- svyglm(m30 ~ ppci, design=design.ps,family=binomial)

This produces the following warning:

`Warning message:`

In eval(expr, envir, enclos) : non-integer #successes in a binomial glm!

Does anyone know what I could be doing wrong ?

I wasn't sure if this message would be better on stats.SE, but on balance I thought I would try here first.

Answer

There's nothing wrong, `glm`

is just picky when it comes to specifying binomial (and Poisson) models. It warns if it detects that the no. of trials or successes is non-integral, but it goes ahead and fits the model anyway. If you want to suppress the warning (and you're sure it's not a problem), use `family=quasibinomial`

instead.