I'm working with a PISA database of student answers to socioeconomic/background questions. Each student (i.e. each observation) has an assigned sampling weight. As there are many questions in the survey (i.e. many variables) I would like to do PCA to some groups of questions and see if the information they contain can be reduced to a small number of indicators.
A similar question was asked here some time ago, but no answer was given:
http://www.stata.com/statalist/archi.../msg00543.html
I think I know how to apply the weights to my data before doing PCA, but the fact that pweights is not simply available as an option makes me nervous that I might be missing something. Is there an obvious reason why pca does not allow pweights?
A similar question was asked here some time ago, but no answer was given:
http://www.stata.com/statalist/archi.../msg00543.html
I think I know how to apply the weights to my data before doing PCA, but the fact that pweights is not simply available as an option makes me nervous that I might be missing something. Is there an obvious reason why pca does not allow pweights?