Hello I have a data.frame of 32 variables, all are ordered factors. str(dat) returns the following 'data.frame': 32 obs. of 43 variables: $ q1a: Ord.factor w/ 6 levels "Strongly Disagree"<..: 3 4 2 5 NA NA 5 5 3 5 ... $ q1b: Ord.factor w/ 6 levels "Strongly Disagree"<..: 3 NA 4 NA NA NA NA 5 4 4 ... $ q1c: Ord.factor w/ 6 levels "Strongly Disagree"<..: NA NA 5 5 NA 4 NA 5 NA 5 ... $ q1d: Ord.factor w/ 6 levels "Strongly Disagree"<..: 5 NA 5 NA NA 5 NA 5 NA 4 ... $ q1e: Ord.factor w/ 6 levels "Strongly Disagree"<..: 5 NA NA 5 5 NA NA 5 5 NA ... $ q1f: Ord.factor w/ 6 levels "Strongly Disagree"<..: 4 5 5 5 5 5 5 4 5 5 ... I'm trying to come up with a polychoric correlation matrix for these, and so I convert them to numeric values: 'data.frame': 32 obs. of 43 variables: $ q1a: num 3 4 2 5 NA NA 5 5 3 5 ... $ q1b: num 3 NA 4 NA NA NA NA 5 4 4 ... $ q1c: num NA NA 5 5 NA 4 NA 5 NA 5 ... $ q1d: num 5 NA 5 NA NA 5 NA 5 NA 4 ... and try: library(psych) polychoric(values, na.rm=TRUE), but this returns the following error The items do not have an equal number of response alternatives, global set to FALSE Error in poly[1, ] : incorrect number of dimensions In addition: Warning message: In mclapply(seq_len(n), do_one, mc.preschedule = mc.preschedule, : all scheduled cores encountered errors in user code Can anyone provide any guidance? Thanks, Simon Kiss ********************************* Simon J. Kiss, PhD Assistant Professor, Wilfrid Laurier University 73 George Street Brantford, Ontario, Canada N3T 2C9 Cell: +1 905 746 7606
William Revelle
2014-Jun-03 00:29 UTC
[R] Help with polychoric correlation in psych library
Simon, As is usually the case with problems with a package, if you write the author/maintainer, you are more likely to get an answer. In this case, I just happened to be readiing R-help (t is the end of the term and I am relaxing). I am happy to look at this if you would send me the data set. What version of the psych package are you using? Bill On Jun 2, 2014, at 3:49 PM, Simon Kiss <sjkiss at gmail.com> wrote:> Hello I have a data.frame of 32 variables, all are ordered factors. str(dat) returns the following > 'data.frame': 32 obs. of 43 variables: > $ q1a: Ord.factor w/ 6 levels "Strongly Disagree"<..: 3 4 2 5 NA NA 5 5 3 5 ... > $ q1b: Ord.factor w/ 6 levels "Strongly Disagree"<..: 3 NA 4 NA NA NA NA 5 4 4 ... > $ q1c: Ord.factor w/ 6 levels "Strongly Disagree"<..: NA NA 5 5 NA 4 NA 5 NA 5 ... > $ q1d: Ord.factor w/ 6 levels "Strongly Disagree"<..: 5 NA 5 NA NA 5 NA 5 NA 4 ... > $ q1e: Ord.factor w/ 6 levels "Strongly Disagree"<..: 5 NA NA 5 5 NA NA 5 5 NA ... > $ q1f: Ord.factor w/ 6 levels "Strongly Disagree"<..: 4 5 5 5 5 5 5 4 5 5 ... > > I'm trying to come up with a polychoric correlation matrix for these, and so I convert them to numeric values: > 'data.frame': 32 obs. of 43 variables: > $ q1a: num 3 4 2 5 NA NA 5 5 3 5 ... > $ q1b: num 3 NA 4 NA NA NA NA 5 4 4 ... > $ q1c: num NA NA 5 5 NA 4 NA 5 NA 5 ... > $ q1d: num 5 NA 5 NA NA 5 NA 5 NA 4 ... > > and try: > library(psych) > polychoric(values, na.rm=TRUE), but this returns the following error > > > The items do not have an equal number of response alternatives, global set to FALSE > Error in poly[1, ] : incorrect number of dimensions > In addition: Warning message: > In mclapply(seq_len(n), do_one, mc.preschedule = mc.preschedule, : > all scheduled cores encountered errors in user code > > Can anyone provide any guidance? > Thanks, Simon Kiss > > ********************************* > Simon J. Kiss, PhD > Assistant Professor, Wilfrid Laurier University > 73 George Street > Brantford, Ontario, Canada > N3T 2C9 > Cell: +1 905 746 7606 > > ______________________________________________ > R-help at r-project.org mailing list > 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. >William Revelle http://personality-project.org/revelle.html Professor http://personality-project.org Department of Psychology http://www.wcas.northwestern.edu/psych/ Northwestern University http://www.northwestern.edu/ Use R for psychology http://personality-project.org/r It is 5 minutes to midnight http://www.thebulletin.org