6.2 CLUSTER ANALYSIS

Cluster analysis is a technique for highlighting the relationships in a grid so

that they become visible at a glance. You would normally use one of the many

software packages accessed through the websites I’ve mentioned in the

introduction to this chapter to do the hard work for you (though if you want to

know how to do cluster analysis by hand, for those moments in life when the

electricity supply fails, Jankowicz & Thomas (1982/1983) provide a detailed

step-by-step manual procedure). My purpose in this section is to

(a) give you a simple rationale by which you can understand how cluster

analysis works, without going into all the detail

(b) provide a procedure for interpreting a cluster-analysed printout.