Hi R-users,

I can not replicate the result for marginal effects from multinomial logistic regression stata output below (http://www.ats.ucla.edu/stat/stata/Library/longutil.htm) The dataset can be found here http://www.ats.ucla.edu/stat/stata/webbooks/logistic/hsblog.dta

PART OF STATA OUTPUT

mlogit: Changes in Predicted Probabilities for prog

female

Avg|Chg| general vocation academic

0->1 .02790104 -.02005389 -.02179766 .04185158

read

Avg|Chg| general vocation academic

MargEfct .0217727 -.0033582 -.00752815 .01088635

math

Avg|Chg| general vocation academic

MargEfct .04519518 -.00711382 -.01548377 .02259759

library(foreign)

library(nnet)

library(VGAM)

hs.data<-read.dta("E:\\hsblog.dta")

head(hs.data)

hs.data$prog<-relevel(hs.data$prog, ref="academic")

mlt.fit<-multinom(prog ~ female+read+math, data = hs.data)

mlt.fit

hs.data$prog<-relevel(hs.data$prog, ref="general")

hs.data$prog<-relevel(hs.data$prog, ref="vocation")

vglm.fit<-vglm(prog ~ female+read+math,multinomial, data = hs.data)

summary(vglm.fit)

So both functions from R provide the same result as on the site.

As I see that the "marginal effects part/Changes in Predicted Probabilities" is not standard output in the 2 functions, can anyone please, tell me how i can get those marginal effects?

PS: I read also http://socserv.mcmaster.ca/jfox/Misc/polytomous-effect-displays/polytomous-effect-displays.pdf but could not obtain the changes in predicted probabilities.

Can anyone give me a hint on how to obtain them?

Thank you very much and have a great day ahead!

Eugen Pircalabelu

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