Dear Xu Jun,
I'm not sure whether this is the source of the error, but it may help to
spell the xlevels argument correctly (it is not "xlevles").
I hope this helps,
John
------------------------------------------------
John Fox
Sen. William McMaster Prof. of Social Statistics
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
http://socserv.mcmaster.ca/jfox/
On Thu, 20 Oct 2011 10:34:30 -0400
Xu Jun <junxu.r at gmail.com> wrote:> Dear r-help listers,
>
> I am using effects to produce an effect plot after the proportional
> odds logistic regression model. There is no problem for me to estimate
> the model, but when it comes to the graphing, I was stuck. see the
> codes below:
>
>
##############################################################################
> myologit <- polr(factor(warm) ~ yr89 + male + white + age + ed + prst,
> + data=ordwarm2, method=c("logistic"))
>
> require(effects)
> plot(effect("age", myologit, xlevles=list(age=seq(20, 80, 5),
> given.values(male=1, yr89=1))))
>
>
##############################################################################
>
> I got the following error message:
>
> Warning message:
> package 'effects' was built under R version 2.13.2
> Error in plot(effect("age", myologit, xlevles = list(age =
seq(20, 80, :
> error in evaluating the argument 'x' in selecting a method for
> function 'plot': Error in model.frame.default(formula =
factor(warm) ~
> yr89 + male + white + :
> variable lengths differ (found for 'yr89')
>
>
> the full set of codes:
>
> > myologit <- polr(factor(warm) ~ yr89 + male + white + age + ed +
prst,
> + data=ordwarm2, method=c("logistic"))
>
> > summary(myologit)
>
> Re-fitting to get Hessian
>
> Call:
> polr(formula = factor(warm) ~ yr89 + male + white + age + ed +
> prst, data = ordwarm2, method = c("logistic"))
>
> Coefficients:
> Value Std. Error t value
> yr89 0.523912 0.079899 6.557
> male -0.733309 0.078483 -9.344
> white -0.391140 0.118381 -3.304
> age -0.021666 0.002469 -8.777
> ed 0.067176 0.015975 4.205
> prst 0.006072 0.003293 1.844
>
> Intercepts:
> Value Std. Error t value
> 1|2 -2.4654 0.2389 -10.3188
> 2|3 -0.6309 0.2333 -2.7042
> 3|4 1.2618 0.2340 5.3919
>
> Residual Deviance: 5689.825
> AIC: 5707.825
>
> > plot(effect("age", myologit, xlevles=list(age=seq(20, 80,
5), given.values(male=1, yr89=1))))
> Warning message:
> package 'effects' was built under R version 2.13.2
> Error in plot(effect("age", myologit, xlevles = list(age =
seq(20, 80, :
> error in evaluating the argument 'x' in selecting a method for
> function 'plot': Error in model.frame.default(formula =
factor(warm) ~
> yr89 + male + white + :
> variable lengths differ (found for 'yr89')
>
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