Thank you, William. Best, Daniel
William Revelle wrote: > > At 6:15 PM -0400 8/21/09, Daniel Malter wrote: >>I have a quick statistical question and hoped somebody has a tip for me >>without me having to go to the local statistician on Monday. >> >>I assess 4 statements from 90 subjects. Each of the 4 statements receives >>one of three responses (say -1, 0, or 1). I can use Cramer's V or Spearman >>correlations to assess the correlation between each pair of statements, but >>I am looking for a measure of coherence across/among all 4 statements. To >>me, this seems to be intraclass correlation. So I was wondering whether I >>can apply it here (specifically, ICC(2,1) or ICC(3,1)) or whether I should >>use an alternative procedure given that my responses are ordinal. >> > > Daniel, > > The intraclass correlation is used if raters are all of the same > ``class". That is, there is no logical way of distinguishing them. > Examples include correlations between pairs of twins, correlations > between raters. If the variables are logically distinguishable > (e.g., different items on a test), then the more typical coefficient > is based upon the inter-class correlation (e.g., a Pearson r) and a > statistic such as alpha or omega might be used. > > The differences between the 3 types of ICCs are the type of > generalization you want to make. > > Note that ICC3n is the same as coefficient alpha. > > ICC, alpha, and omega are all part of the psych package. > > Bill > > -- > William Revelle http://personality-project.org/revelle.html > Professor http://personality-project.org/personality.html > 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 > > ______________________________________________ > R-help@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. > > -- View this message in context: http://www.nabble.com/intra-class-correlation--coherence-among-multiple-ordinal-responses-tp25088149p25097519.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@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.
