[R] Error using nlme; Malformed factors

[Bert Gunter]

You may do better (faster, more knowledgeable responses) posting on
the r-sig-mixed-models list.

-- Bert


Bert Gunter

"The trouble with having an open mind is that people keep coming along
and sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Tue, Dec 20, 2016 at 6:24 PM, Wong Yoke Yong <yokeyong.wong at gmail.com> wrote:
> HI all,
>
> I am using the nlme package to learn multilevel models, and following
> examples from the textbook "Discovering Statistics Using R" when it
> happened.
>
> [Mixed Models Code][1]
>
> The data set is Honeymoon Period.dat, also downloadable under their
> companion website.
>
> [Data Set - Multilevel Models][2]
>
>     require(nlme)
>     require(reshape2)
>     satisfactionData = read.delim("Honeymoon Period.dat",  header = TRUE)
>
>     restructuredData<-melt(satisfactionData, id = c("Person", "Gender"),
> measured = c("Satisfaction_Base", "Satisfaction_6_Months",
> "Satisfaction_12_Months", "Satisfaction_18_Months"))
>     names(restructuredData)<-c("Person", "Gender", "Time",
> "Life_Satisfaction")
>
>
>     #print(restructuredData)
>     #restructuredData.sorted<-restructuredData[order(Person),]
>
>     intercept <-gls(Life_Satisfaction~1, data = restructuredData, method =
> "ML", na.action = na.exclude)
>     randomIntercept <-lme(Life_Satisfaction ~1, data = restructuredData,
> random = ~1|Person, method = "ML",  na.action = na.exclude, control =
> list(opt="optim"))
>     anova(intercept, randomIntercept)
>
>     timeRI<-update(randomIntercept, .~. + Time)
>     timeRS<-update(timeRI, random = ~Time|Person)
>     ARModel<-update(timeRS, correlation = corAR1(0, form = ~Time|Person))
>
> The error occured at this moment, when I am trying to update "timeRS"
> model. The error is as follows:
>
>     Error in as.character.factor(X[[i]], ...) : malformed factor
>
> Help would be appreciated. Thanks!
>
>   [1]:
> https://studysites.uk.sagepub.com/dsur/study/DSUR%20R%20Script%20Files/Chapter%2019%20DSUR%20Mixed%20Models.R
>   [2]: https://studysites.uk.sagepub.com/dsur/study/articles.htm
>
>
> Regards,
> Yoke Yong
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.