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Re: st: logit / odds ratio interpretation using -listcoef-


From   Jn <ensam21@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: logit / odds ratio interpretation using -listcoef-
Date   Fri, 21 Mar 2008 18:01:53 -0400

thanks for your clarification!

On Sat, Mar 15, 2008 at 11:26 AM, Maarten buis <maartenbuis@yahoo.co.uk> wrote:
> Yes, that can happen, for instance in the example below the odds of
>  being in good repair is ~1900% larger for foreign cars than for
>  domestic cars:
>
>  sysuse auto, clear
>  recode rep78 1/3=0 4/5=1
>  logit rep78 foreign , or
>  listcoef, percent
>
>  In this case the odds ratios compares the likelihood of being in good
>  repair of foreign and domestic cars. The likelihood is represented with
>  odds: the number of carrs in good repair for every car in bad repair.
>  To gain a bit more confidence in this result you might want to know
>  what the odds of being in good repair is for domestic cars. This you
>  would get if Stata also reported exp(_cons) when you asked for the -or-
>  option, unfortunately Stata doesn't do that (I know, I have asked for
>  that a number of times). However, you can trick Stata in doing that:
>
>  gen one = 1
>  logit rep78 one foreign , or nocons
>
>  For every domestic car in bad repair there are only ~.30 cars in good
>  repair. If we multiply this by the odds ratio we get the odds of being
>  in good repair for foreign cars:
>
>  di exp(_b[foreign])*exp(_b[one])
>
>  For every foreign car in bad repair there are 6 cars in good repair. We
>  could get those two odds in one go by adding both a dummie for domestic
>  and a dummy for foreign cars (and leave out the constant):
>
>  gen domestic = !foreign
>  logit rep78 domestic foreign, nocons or
>
>  I hope this helps,
>  Maarten
>
>
>
>
>  --- Jn <ensam21@gmail.com> wrote:
>
>  > Dear Stata users,
>  >
>  > I am a student and I have one question regarding interpretation of a
>  > logit regression. After running my regression I used -listcoef-
>  > command (in percentage form) for interpretation of the coefficients.
>  > Some of my dummy independent variables return with extremely high
>  > percentage chnage in odds i.e. 2,500% and I am not sure if I am
>  > interpreting this right. Does that mean the odds of my dependent
>  > variable = 1 increase by 2500% for ___??___ (i don't get this part,
>  > when the independent variable is binary). Would it make sense for me
>  > to interpret it as, for instsance, a 0.5 increase in probability of x
>  > variable increases the odds of y=1 by 1250 %?
>  >
>  > Any help appreciated..thanks
>  > *
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>
>
>  -----------------------------------------
>  Maarten L. Buis
>  Department of Social Research Methodology
>  Vrije Universiteit Amsterdam
>  Boelelaan 1081
>  1081 HV Amsterdam
>  The Netherlands
>
>  visiting address:
>  Buitenveldertselaan 3 (Metropolitan), room Z434
>
>  +31 20 5986715
>
>  http://home.fsw.vu.nl/m.buis/
>  -----------------------------------------
>
>
>
>       ___________________________________________________________
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>
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