For my PhD thesis I have to do a Principal Component Analysis (PCA). I didn't find it too difficult in STATA and was happy interpreting the results.

(I am well aware that there is a difference between factor and principal component analysis).

However, I discussed it with a colleague who uses SPSS, so I imported my data (from Excel) into SPSS too, and performed the PCA in there as well.

Shockingly for me, the results differed enormously from my STATA results. Not even close to it (even different number of components in the end).

How can that be? I did do a PCA in STATA as well as in SPSS for sure and the dataset is the same.

Even stanger to me: When I did

What is principal-component factors? A mixture of PCA and factor analysis?

I am confused. If people report in journals having done a PCA - should I then ask, with SPSS or STATA?

Could anyone explain it to me? I'd be very greatful!

Thanks very much for your help!

Hanne

P.S. I attached the output of both, SPSS and STATA after rotation (varimax, kaiser on, blanks(.4) and based on an eigenvalue>1 both retained 3 compnents).

(I am well aware that there is a difference between factor and principal component analysis).

However, I discussed it with a colleague who uses SPSS, so I imported my data (from Excel) into SPSS too, and performed the PCA in there as well.

Shockingly for me, the results differed enormously from my STATA results. Not even close to it (even different number of components in the end).

How can that be? I did do a PCA in STATA as well as in SPSS for sure and the dataset is the same.

Even stanger to me: When I did

**FACTOR varnames, PCF (principal-component factor) in STATA**I received (almost) the same results as for the PCA in SPSS.What is principal-component factors? A mixture of PCA and factor analysis?

I am confused. If people report in journals having done a PCA - should I then ask, with SPSS or STATA?

Could anyone explain it to me? I'd be very greatful!

Thanks very much for your help!

Hanne

P.S. I attached the output of both, SPSS and STATA after rotation (varimax, kaiser on, blanks(.4) and based on an eigenvalue>1 both retained 3 compnents).

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