I want to do clustering of my data in R, using kmeans or hclust (I am a new R user).
My data is ordinal, Likert scale, to measure the causes of cost escalation. I have 41 causes "variables" that scaled from 1 to 5 (1: no effect, 5: major effect). I have about 160 observations "who rate the causes".
I would like to cluster the variables (the columns, not the rows) in terms of similarity of occurrence in observations, but I don't know how to start.
Do I have to convert the scale to percentage or z-score before clustering?
My data is available and shared as a Google Drive spreadsheet.