Re: st: Calculating predicted probabilities at a given value of one of the independent variables

[Richard Williams <richardwilliams.ndu@gmail.com>]

At 06:06 PM 10/26/2011, Maria Ana Vitorino wrote:
> Dear Statalist users,
>
> I would like to calculate some predicted probabilities after fitting a
> multinomial logit model (asclogit). But, the twist is that I would
> like to calculate these fitted values for a given level of one of the
> independent variables. Namely, I would like to set one of the Xs to
> zero when computing the predicted probability (but not in the
> estimation).
> What would be the best way of going about this? Would it make sense to
> do it in 2 steps? In the first step use  "predict xb" and in the
> second step remove the component of xb that I'm not interested and
> calculate the probability using "gen" and the logit formula?
> Or is there a better way?

I am going to slightly tweak my earlier advice. Assuming you only 
want in-sample predictions,

webuse sysdsn1, clear
clonevar xmale = male
mlogit insure age i.xmale nonwhite i.site
predict p1 p2 p3 if e(sample)
replace xmale = 0 if !missing(xmale)
predict pp1 pp2 pp3 if e(sample)


-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
HOME:   (574)289-5227
EMAIL:  Richard.A.Williams.5@ND.Edu
WWW:    http://www.nd.edu/~rwilliam

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