Dear Oscar, and any other R-project person, Can you please help me to figure out the meaning of the following error message in red ?
Error in eval(predvars, data, env) : numeric 'envir' arg not of length one I computed ordered logit models using 'polr' in R (I just followed the guidance a handout I found on princeton.edu about logit, probit and multinomial logit models) . The summary results are obtained without any problem. *However*, when I'm using the package 'erer' to compute the marginal effects for the ordered logit models, I'm just getting the error message above. Please HELP !!!! Willy -- Willy Mulimbi B. AEAB Grad Student & Fulbright Scholar Tel. (+1) 479-316-5981 Fayetteville, AR [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.