Dear Statalist:
I want to know how to develop an index from 5 ordinal variables. But I am not sure about standardization of ordinal variables and how to use weights to develop an index. The ordinal variables are in Likert scale from 1 to 4.
I am thinking of using eigenvectors of the first component of polychoric PCA (with code of 'polychoricpca'). I believe that this code is for ordinal variables so that I don't need to standardize the variables before I run polychoric PCA. ( Before I run polychoric PCA, I checked Kendall tau b and MCA.).
But after that, I think that I need to standardize ordinal variables to calculate the index with weights (eigenvectors). If so, how can I standardize ordinal variables? And then I multiply each variable by weight from the pca and sum up to make an index.
I want to know if this procedure is correct or not. This index is one of explanatory variables. I just want to know a simple method to develop an index.
Thank you very much for your help in advance.
Best regards,
Hisako
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Hisako Kobayashi
[email protected]
Ph.D Candidate in Public Administration
School of Policy, Planning and Development University of Southern California
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