Basic factor analysis in R

February 17, 2006
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(This article was first published on Dataninja » R, and kindly contributed to R-bloggers)

The call to perform factor analysis on a set of variables in R is:

fact1<- factanal(x,factors,scores=c(“regression”),rotation=”varimax”)

where “x” is a dataframe containing the appropriate variables, and “factors” is the number of factors to be extracted.

socres=”…” and rotation=”…” are optional, and varimax is the default rotation.

The factanal function doesn’t seem to handle missing observations well, so it’s easier to create a new dataframe based on your original, with the missing values omitted:

x1<-na.omit(x)

To view the summary of the factor analysis, simply type the name of the object under which the analysis was saved.

fact1

To view the scores, use

fact1$scores

To view a scree plot, install the “psy” package load it

install.packages(“psy”)
library(psy)

Then type

scree.plot(fact1$correlations)

The above commands and options are only the very basics. For more information, view the documentation for the factanal function. For more information about factor analysis in general, here is a nice nontechnical introduction.


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