topic Re: PCA total variable contribtion in Discussions

PCA total variable contribtion

FN — Fri, 09 Jun 2023 21:59:17 GMT

I would like to get a list of variables ordered by their contribution explaining the variability within the data.

In PCA, one can plot the partial contribution of the variables. However, this visualization does not consider the different importance between PCs. The eigenvalues table includes the percentage of data explained.

Is there a way to get the total variable contribution?

Re: PCA total variable contribtion

Thierry_S — Sat, 28 Nov 2020 19:37:09 GMT

Hi,
I'm not aware of a direct method to get to the Total Contribution values but here is a possible work around (not particularly elegant) that may do the job for you.
1) Save the Partial Contribution table (right click > make into table)
2) Transpose the resulting table
3) Save the EigenValues table into a new table
4) Copy the Percent column to your Partial Contribution table
5) Calculate the product of each partial contribution by the corresponding Eigenvalues
This is rather labor intensive so if you have to retrieve this information for multiple tables, you may want to look into scripting those steps.
Best,
TS

Re: PCA total variable contribtion

ih — Tue, 01 Dec 2020 23:00:19 GMT

Hi @FN,

I think you are looking for loadings, or the eigenvectors * sqrt( eigenvalues ). These are calculated in the PLS platform within JMP but not PCA. Here is how I would go about that interactively for PCA:

(view in My Videos)