Posted by
Phil Higgins, MSW, LICSW on
Mar 20, 2012; 12:55pm
URL: http://spssx-discussion.165.s1.nabble.com/factor-analysis-with-dichotomous-yes-no-and-ordinal-variables-tp5580143.html
Hello,
I know there have already been a number of posts related to FA with
dichotomous variables, but in reviewing them I'm still left unclear about
the best approach for my situation.
I am working with a dataset from which I have extracted 18 items, some of
which are dichotomous (Yes/No responses) and some of which are ordinal (5-
or 7-point Likert). All of these are related to caregiver opinions on end-
of-life care for their loved one.
My research focus is on a larger phenomenon which isn't addressed directly
in the dataset, but which I believe may be a latent construct represented
by these 18 items.
I would like to test my hypothesis and see whether or not these
items "hang together" in factor analysis, but I am not sure about the best
approach. I have access to LISREL/PRELIS and SPSS (as well as STATA, but
I haven't used it before). I understand that the necessary steps involve
computing a correlation matrix, and then "plugging" that into a program
for analysis. My questions:
1. In attempting to compute a correlation matrix on LISREL, it gives me
the option for classical and ordinal. Do I select ordinal? If so, will
LISREL automatically know which are dichotomous and which are ordinal, and
choose the correct type of correlation? I have read about tetrachoric and
polychoric correlation - - does LISREL/PRELIS calculate these on its own?
2. Do I need to transform my Yes/No items to dummy variables? At present,
they are designated as 1=yes, 2=no
3. Once I have the matrix, what is the best approach to analyzing it via
SPSS? Or is there a better readily accessible program?
4. Is classic factor analysis the best approach? As opposed to PCA or
Latent Class Factor Analysis?
I apologize for the elementary level of my questions - I am a 3rd year
doctoral student and we didn't cover this in my coursework thus far. Does
anyone know of a good online resource that could guide me through this
whole process in step-by-step fashion...??
Thanks for any guidance. I'm sure I missed some key questions to consider,
please feel free to set me back onto the right path!
Phil Higgins, MSW, LICSW
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