conducting factor analysis on polychoric correlation

PsycResearcher — Thu, 06 Oct 2011 17:54:07 GMT

Hi,

I have a question about conducting factor analysis on polychoric correlation. I have a correlation table in the following format in SAS:

A	B	C	D	E
1	.1	.2	.5	.4
.1	1	.4	.6	.2
.2	.4	1	.2	.4
.5	.6	.2	1	.1
.4	.2	.4	.1	1

A B C D E are the variables in the dataset (the actual dataset has 17 variables), with 1000 observations.

I conduct the factor analysis with the following syntax:

PROC FACTOR data =matrix1 (TYPE=CORR)

METHOD = ULS NFACTOR= 3 NOBS= 1000

ROTATE = v SCREE CORR;

RUN;

SAS complains the following:

(MESSAGE 1)

No _NAME_ variable in the TYPE=CORR data set WORK.MATRIX1. Be sure that the variables are specified in the same order as the corresponding observations appear in the dataset.

(MESSAGE 2)

The CORR matrix read from the input dataset WORK.MATRIX1 has a diagonal element equal to 0.999999 for the variable A.

The CORR matrix read from the input dataset WORK.MATRIX1 has a diagonal element equal to 0.999999 for the variable B.

The CORR matrix read from the input dataset WORK.MATRIX1 has a diagonal element equal to 0.999999 for the variable C.

The CORR matrix read from the input dataset WORK.MATRIX1 has a diagonal element equal to 0.999999 for the variable D.

The CORR matrix read from the input dataset WORK.MATRIX1 has a diagonal element equal to 0.999999 for the variable E.

So, SAS does not allow any 1's in a correlation matrix? When A correlates with A, for example, the correlation will naturally be 1. Why is SAS complaining?

Any help will be useful.

Thanks!

Chester

Re: conducting factor analysis on polychoric correlation

Ksharp — Fri, 07 Oct 2011 06:41:46 GMT

It looks like your correlation table matrix1 (TYPE=CORR) has not proper format about SAS CORR TABLE.

Should like:

_type_ _name_ p1 p2 p2 p4

CORR P1 1.0

CORR P2 .39 1.0

..............................

CORR P4 ..................1.0

N N 123 123 123 123

Ksharp

conducting factor analysis on polychoric correlation

Rick_SAS — Mon, 10 Oct 2011 12:57:05 GMT

FOr a description of the TUPE+CORR data set, see

http://support.sas.com/documentation/cdl/en/statug/63962/HTML/default/viewer.htm#statug_appssds_sect008.htm

topic conducting factor analysis on polychoric correlation in Statistical Procedures

conducting factor analysis on polychoric correlation

Re: conducting factor analysis on polychoric correlation

conducting factor analysis on polychoric correlation