Hello,
I am trying to estimate average treatment effect in the MatchIt package
(current R version on Windows), and ran the model exactly as in the
documentation page 13, 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 R help list at the moment.

Thanks Marwan Khawaja

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