Solved – Cluster analysis on ordinal data

clusteringlikertordinal-dataspss

I'd like to perform a cluster analysis on ordinal data (Likert scale) by using SPSS. I have around 140 observations and 20 variables that are scaled from 1 to 5 (1: I strongly agree, 3: neutral, 5: I strongly disagree). As a result, I want to assign one cluster to each person, such as person 1 belongs to the group of technology-enthusiastic users…

Since I'm new in that area, I want to ask you, if you might help me with regard to the procedure. I have already read something about cluster analysis in the Internet, but there are different opinions on how to treat ordinal data.

Is it a common way to convert the ordinal data to interval data first and then perform the cluster analysis?

Best Answer

If you can define a reasonable similarity measure on the values, you can use any distance based algorithm, such as:

  • Hierarchical clustering
  • DBSCAN
  • OPTICS
  • K-Medoids (k-means for arbitrary distances)

Given that you only have 5 values, you could just manually define a similarity matrix for these 5 values; then decide on a combination rule to merge multiple attributes, e.g. mean.

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