Dear Statalist,
I file to plot Confidence interval of margin contrast of dummy variables.
I am using coefplot from SSC Jann, B. (2014). Plotting regression coefficients and other estimates. The Stata Journal 14(4): 708-737.
my code looks like

[ sysuse auto, clear
* dummy and contrast (NOT plotting CI )
cap drop price2
recode price (min/10000 = 0) (10000/max = 1), gen(price2)
qui ologit rep78 i.price2##i.foreign
margins , dydx(price2) over(r.foreign) contrast(effect) post pr(outcome(1))
matrix list e(b)
matrix list e(V)][/CODE]

Interestingly, the issue is due when I compute contrast of margins and dummy at the same time.

When the variable is continuous I do not have this issue :
[ * continuous and contrast
qui ologit rep78 c.price##i.foreign
margins , dydx(price) over(r.foreign) contrast(effect) post pr(outcome(1))
matrix list e(b)
matrix list e(V)
coefplot][/CODE]

The issue is absent also when there is no contrast
[ * dummy and no contrast
qui ologit rep78 i.price2##i.foreign
margins , dydx(price2) over(foreign) post pr(outcome(1))
matrix list e(b)
matrix list e(V)
coefplot][/CODE]

Any help is really wellcome

Cesare Riillo