[R-sig-ME] Is it ok to use lmer() for an ordered categorical (5 levels) response variable?

Stuart Luppescu |upp @end|ng |rom uch|c@go@edu
Thu Mar 7 03:02:42 CET 2019

On Wed, 2019-03-06 at 16:49 +0000, Pierce, Steven wrote:
> Many researchers refer to a survey instrument as a scale, refer to
> the sum of the items from such an instrument as a scale score, then
> go on to use such scores in their research. That's the sense in which
> I am using the term scale score. It's obviously a looser, more
> informal usage than you prefer but that doesn’t mean I'm wrong. It's
> an empirical fact that lots of people use the term the way I did. 

I'm with Harold Doran on this one (not for the first time by any
means). Just because a lot of people do it doesn't have anything to do
whether it's a good method or not. When I was in graduate school a long
time ago we learned that the numerical codes associated with the
response categories for survey data are category labels, nominal data,
not numeric data. And as such it is not appropriate to do arithmetic
(such as calculating sums and means) on them.
Stuart Luppescu
Chief Psychometrician (ret.)
UChicago Consortium on School Research

lupp using uchicago.edu

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