st: wealth score using principal component analysis (PCA)

[Shikha Sinha <shikha.sinha414@gmail.com>]

Dear Statalist,

I am trying to create a wealth score using the ownership of different
assets in the DHS survey.  I am suing -pca but I am not sure how to
estimate the score as I want to use the wealth score as one of the
independent variables.

pca x1-x4
predict p1,score

but -predict only generates score from first component.

I also tried the following,

-pca x1-x4, components (2)
predict p2, score

However, p1 and p2 are same.

My questions are, (a) why there is no difference between p1 and p2?
(b) How can I generate score by using first 2 components only?
(c) Is it ok to use continuous pca score as an independent variable?

Thanks,
Shikha
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