# Re: st: RE: prvalue / dummy variables

 From "Jochen Hirschle" To statalist@hsphsun2.harvard.edu Subject Re: st: RE: prvalue / dummy variables Date Tue, 04 Jul 2006 17:49:38 +0200

```thank you for your reply Marteen.
Do you (or someone else on this list) know a possibility of how I could predict those probabilities (after multinomial regression) not for individuals – where saying that he / she is 52% female sounds indeed strange - but for two groups which have an identical underlying demographic structure (52% females; 48% males) but completely differ in one other aspect (say the one group containing 100% high educated persons where the other group containing 100% low educated persons)?

Thank you once again.
Jochen

-------- Original-Nachricht --------
Datum: Tue, 4 Jul 2006 11:53:10 +0200
Von: Maarten Buis <M.Buis@fsw.vu.nl>
An: statalist@hsphsun2.harvard.edu
Betreff: st: RE: prvalue / dummy variables

> --- Jochen Hirschle wrote:
> > My question concerns the use of dummy-variables
> > within prvalue. As I only wish to control for
> > certain (dummy)variables (sex, place of birth,
> > etc.) and didn't wanted to produce separate
> > estimations for each value (e.g. sex=0, sex=1),
> > I was using the mean option for the dummy
> > variables just as for metric variables
> > (e.g. age). Does that make sense? How can I
> > interpret the estimated probabilities then? Can
> > I say that these probabilities apply for a group
> > which has an underlying structure concerning sex,
>
> Jochen:
> Say you are calculating the probabilities for
> different values of age but keep the effects of
> other variables at their mean, than you are looking
> at how the probability changes as age changes for
> an otherwise "mean/normal/typical" person. So if
> you keep the variable sex at it's mean you are
> looking at the effect of age for someone who is say
> 52% female. Now, some would argue that someone who
> is 52% female is not very typical, but you can also
> see this as averaging the effect of age over males
> and females. I have no problems with the latter
> interpretation but others do. So it is probably easier
> to use for nominal variables like sex and birthplace
> the mode to choose the "typical" individual, i.e. fix
> continuous variables at their mean and nominal
> variables at their mode.
>
> HTH,
> Maarten
>
> -----------------------------------------
> Maarten L. Buis
> Department of Social Research Methodology
> Vrije Universiteit Amsterdam
> Boelelaan 1081
> 1081 HV Amsterdam
> The Netherlands
>
> Buitenveldertselaan 3 (Metropolitan), room Z214
>
> +31 20 5986715
>
> http://home.fsw.vu.nl/m.buis/
> -----------------------------------------
>
>
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