Re: st: Obtaining rrr's of margins after mlogit

[John Francis <francisj71@googlemail.com>]

Thank you so much Maarten, this is exactly what I was looking for!

John

On Thu, Mar 22, 2012 at 1:56 PM, Maarten Buis <maartenlbuis@gmail.com> wrote:
> On Thu, Mar 22, 2012 at 12:03 PM, John Francis wrote:
>> Now, what do I do in order to check how much the effect has changed
>> between cohorts, and whether or not said change is significant? How
>> does the constant play into this? I think these things would be fairly
>> obvious to see if I could use -margins, over()-, but as it is, the
>> -mlogit- output is quite confusing to me...
>
> I think what you are looking for what is discussed in
>
> M.L. Buis (forthcoming) "Stata tip 106: With or without reference",
> The Stata Journal, 12(1).
> <http://www.maartenbuis.nl/publications/ref_cat.html>
>
> With these tricks you can easily get separate relative risk ratios for
> each category, which is sometimes easier to understand. To create an
> example with -mlogit-:
>
> *------------------------ begin example -------------------------
> sysuse nlsw88, clear
>
> gen occ_cat = cond(occupation < 3                 , 1,      ///
>              cond(inlist(occupation, 5, 6, 8, 13), 2, 3))  ///
>              if occupation < .
> label define occ_cat 1 "high"   ///
>                     2 "middle" ///
>                     3 "lower"
> label value occ_cat occ_cat
>
> gen marst = never_married + 2*married
> label define marst 1 "divorced/widowed" ///
>                   2 "never married"    ///
>                   3 "married"
> label value marst marst
>
> gen c_grade = grade - 12
>
> mlogit occ_cat ibn.marst ibn.marst#c.c_grade, rrr nocons
> *------------------------- end example --------------------------
> (For more on examples I sent to the Statalist see:
> http://www.maartenbuis.nl/example_faq )
>
> So the relative risks comparing high with lower occupations (in the
> panel labeled "high") for divorced/widowed is .54 person with a higher
> job for every person with a lower job. Similarly, for never married it
> is .38 person with a higher job for every person with a lower job and
> for married it is .43 persons with a higher job for every person with
> a lower job. All these relative risks (I like to call them odds [*])
> refer to persons with high school (12 years of education).
>
> A year increase in education is associated with an increase in the
> relative risks by a factor 1.23, 1.44, and 1.29 for divorced/widowed,
> never married, and married persons respectively.
>
> Hope this helps,
> Maarten
>
> [*] <http://www.stata.com/statalist/archive/2007-02/msg00085.html>
>
> --------------------------
> Maarten L. Buis
> Institut fuer Soziologie
> Universitaet Tuebingen
> Wilhelmstrasse 36
> 72074 Tuebingen
> Germany
>
>
> http://www.maartenbuis.nl
> --------------------------
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