It is all right with FA based on variables measured on different scales and/or having different variance.
But you should decide if you are going to base FA on correlations or covariances. You may want to check these threads: https://stats.stackexchange.com/q/62677/3277 ; https://stats.stackexchange.com/q/53/3277.
Doing the analysis on correlations (a more frequent decision) saves you from thinking about prior linear rescaling both your scales to a common one, such as range to 0-1 scale - because Pearson r is insensitive to linear transforms of data.
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Kirill Orlov
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Original Message:
Sent: Wed June 12, 2024 09:27 AM
From: Bob Silagi
Subject: Factor Analysis in SPSS
Hi all,
I have a two-part question:
1) If I'm conducting a factor analysis can the variables I use have different numbers of points on their scales? For example, can I use some variables with a seven-point agree/disagree scale, and some with a six-point "completely describes me" scale? Or do I need to somehow standardize the scales before I do a factor analysis?
2) If I need to standardize, how do I do that in SPSS?
Thanks!
Bob