st: interpreting probit coefficient

[Paul Byatta <paulbyatta@gmail.com>]

Hi Stata list

I kindly need help with interpreting coefficients from a probit
regression. I have a dataset and I want to examine how years of
marriage, polygamy, dowry payment predict probability of domestic
disputes among married couples in a country.

I have run the command below

 probit m181_dispute m3_yea m7a m11a, r

I followed that with

 margin, dy/dx(*)

my variable names are

m181_dispute = 1 if there was a domestic dispute, 0 if otherwise
m3_yea = length of marriage in years
m7a =  1 if husband has more than 1 wife, 0 if has 1 wife
m11a = 1 if husband has paid dowry, 0 if not

After I run the margin command, I get

                dy/dx
 m3_yea |   .0050716
 m7a |    .021586
 m11a |  -.0608191
m12a |  -.0176505


I understand that, because m3_yea is a continuous variable, it would
be accurate to interpret the marigin coefficient on m3_yea as 1
additional year of marriage would on average decrease probability of
occurrence of domestic disputes by 0.5 percent.

I am, however, confused as to how to interpret a margin coefficient on
an indicator variable. For instance, I was wondering whether it would
be accurate to interpret the margin coefficient on m7a  as the
probability of domestic disputes occurrence in marriages with more
than 1 wife is on average higher by 2.16 percent than in those with
one 1 wife.


Thanks
Paul
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