Two-Step Cluster Analysis

What is Cluster Analysis?
Cluster analysis is a statistical technique used to group cases (individuals or objects) into homogeneous sub-groups based on responses to variables. Using PASW (SPSS) 17.0 to conduct a cluster analysis, there are three clustering procedures: two-step, k-means, and hierarchical.

Two-step clustering handles large datasets and continuous and categorical variables (this is the only clustering procedure that allows for a mixture of variables). In the first step, cases are assigned into pre-clusters and these pre-clusters are treated as single cases in the second step. In the second step, the hierarchical algorithm is used to cluster the pre-clusters. You can allow the two-step algorithm to determine the number of clusters or you can specify the number of clusters.

Summary of files below:

  • Two-step Handout.pdf: an instructional guide on how to conduct a two-step cluster analysis in PASW
  • TwoStepData.xls: sample data file to run two-step cluster analysis (need to upload excel file into PASW)
  • TwoStepOutput.pdf: output of two-step cluster analysis
Two-step_Handout.pdf354.07 KB
TwoStepData.xls107 KB
TwoStepOutput.pdf47.74 KB