Hello,
I am trying to estimate average treatment effect in the Zelig package
(current R version on Windows), and ran the model exactly as in the
documentation page 18 of the MatchIt package, and got the following error massage,
ate.all<-c(s.out61$qi$att.ev, -s.out62$qi$att.ev)Error in
-s.out62$qi$att.ev : invalid argument to unary operator
(s.out62 is similar to s.out2 in the example0
Appreciate your help.
Kindly respond to my private email - am not a
subscriber to list at the moment.
Thanks Marwan Khawaja