[R] help with summary(polr_model)

[Luca Braglia]

hello everybody

I'm a newbie with ordered probit and with polr too.
The problem is that I have a dependent variable I need to explain
with an ordered probit that is

> head(dfscale$sod.sit.ec.fam,100)
>   [1]  5  7  5  6  5  5  6  8  6  8  8  8  6  6  6  5  0  5 NA  6
>  [21]  7 NA NA  0  0  2  5  3  6  6  7  6 NA  8  6  6  7 NA NA NA
>  [41]  4  5 NA 10  3  9 10 10  7  5  5  5 NA NA  5  7  1  1  7  3
>  [61]  6  7 NA  4  6 NA  3  4  5  3  4  4  4  5 NA  2  4  4  8  5
>  [81]  5  4  6  6  5  6  7  7  7  7  7  6  8  7  6  5  5  5  6  7

so when I estimate the model

> base.op <- polr(
>                 as.ordered(sod.sit.ec.fam) ~
>                 log(y) +
>                 log(ncomp) +
                
>                 eta +
>                 I(eta^2) +
>                 uomo + 
>                 elem +
>                 laurea +
>                 saluteno +
>                 extra
>                ,
                
>                 weights = dfscale$w,
>                 data = dfscale,
>                 method = "probit"

>                 )


I get

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


Then when I try to summarize the model, in order to use xtable


> summary(base.op)

> Re-fitting to get Hessian

> Errore in optim(start, fmin, gmin, method = "BFGS", hessian =
> Hess, ...) : 
>   valore iniziale in 'vmmin' non finito


that freely translated to english means "starting value in
'vmmin' not finished (or finite, more likely)"

what does this mean? How can I have my summary?


Thank you 

  Luca


-- 
             Luca Braglia, aka Bragliozzo
           http://bragliozzo.altervista.org