# RE: st: RE: Fractional Logit

 From "Nick Cox" To Subject RE: st: RE: Fractional Logit Date Sun, 30 Oct 2005 16:44:00 -0000

```If that is a possibility, so also is the -betafit-

Nick
n.j.cox@durham.ac.uk

Clive Nicholas

> Rijo John replied to Nick Cox:
>
> > Thanks Nick. I am trying to estimate the impact of spending on a
> > particular commodity (say X) on the purchase of other goods
> and services.
> > So I have the share of, say commodity Y (Its share in
> household budget)
> > as the dependent variable and the expenditure on commodity X along
> with
> > various control variables for household as explanatory
> variables. This
> > can be a standrad OLS estimation. But since the depended
> variable is a
> > fraction and  is bound between 0 and 1 we go for fractional
> logit model.
> >
> > I hope this clarifies the problem. Given this I would like
> to know what
> > would be the right choice of family and link in GLM.
> >
> > "family(gaussian) link(logit)" or "family(binomial)
> > other combination?
> >
> > in "family(binomial) link(logit)" is it tru that stata
> takes all values
> > other than 0 in the dependent variable as 1. If thats the
> case it does
> > not take the budget share (absolute amount) information
> into account. It
> > will only see if the budget share is absent or not.
>
> Since your dependent variable is a fractional, or 'compositional',
> variable ranging continuously from 0 to 1, another
> alternative is to use
> Sean 'Jack' Buckley's -mlbeta-. This allows maximum
> likelihood estimation
> with Beta-distributed dependent variables, as well as
> modelling separate
> equations for both a mean and dispersion effect. This routine is _not_
>
> . net from http://www2.bc.edu/~bucklesj
>
> and then click on -mlbeta-. Hope that helps.

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