Hi! I'm conducting a research which involves matching in R. I'm running now an old code, written by a colleague, who passed away last year. I'm trying to continue his research, but I encountered some issues while reviving his code. The main problem is that I'm not familiar with Zelig functionalities, so I can't even tell if the problems that I encountered are due to changes in Zelig packages over the years, or not. In his original code, my colleague wrote: z.treat <- zelig(OF, data=CNTRL_G, model="ls") x.treat <- setx(z.treat, data=TREAT_G, cond=TRUE) s.treat <- sim(z.treat, x=x.treat) z.control <- zelig(OF, data=TREAT_G, model="ls") x.control <- setx(z.treat, data=CNTRL_G, cond=TRUE) s.control <- sim(z.control, x=x.control) att <- s.treat$qi$att.ev ate <- c(s.treat$qi$att.ev, -s.control$qi$att.ev) However, when I try to run this code, I get the following error: Error in s.treat$qi$att.ev : object of type 'closure' is not subsettable I tried to install an old version of Zelig, but this resulted in hundreds of warning and no success in running the abovementioned methods. I understand that Zelig package has gone through some changes with regards to retrieving ATT, however, I'm afraid to harm the original code's meaning and would like to know what is the exact corresponding code in the new version, so that my colleague's results will remain as originally computed. Could you please help me with this issue? I would really appreciate your advice regarding the replacement of the code with a code which will produce similar results, with the new format of the newer Zelig package. Thanks in advance, Yael [[alternative HTML version deleted]]