[R] Struggling to compute marginal effects !

Jim Lemon drjimlemon at gmail.com
Mon Mar 19 23:33:56 CET 2018

Hi Willy,
The error message may be due to passing an inappropriate environment.
I don't have the "erer" package, but if that function has a default
for the environment argument, perhaps passing just the "predvars" and
"data" arguments will work.


On Tue, Mar 20, 2018 at 8:24 AM, Willy Byamungu <wmulimbi at email.uark.edu> wrote:
> 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]]
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