This article describes how to do a kmeans cluster analysis in Displayr. The kmeans cluster analysis algorithm is a method for grouping similar cases into groups, or clusters. The final clusters will be different from each other, while the cases within a cluster are broadly similar to each other.
Requirements
 A data set containing the variables that you want to use as inputs to the cluster analysis segmentation.
 Familiarity with the Structure and Value Attributes of Variable Sets.
Method
1. From the toolbar, select Anything > Advanced Analysis > Cluster > KMeans Cluster Analysis. A cluster analysis object will added to the current page.
2. From the object inspector, select the inputs (clustering variables) from the Variables dropdown in the Inputs section. For this example, we've selected 11 behavioral/attitudinal statements on mobile technology. Questions were asked as a 5point agree/disagree scale. We'll use the top 2 box responses to each of the statements as the inputs to our kmeans cluster analysis.
You can use any other numeric variables as clustering variables that can potentially provide differentiation between the respondents and therefore help define the clusters.
Note that if the variables are grouped in a Variable Set, then the Variable Set may be selected instead, which is more convenient than selecting multiple variables.
3. Select the number of clusters that you want to create in the Number of clusters field. I've selected 3 clusters for this example, but you can choose any value you want here.
4. Optional: Modify any of the other input settings as desired. For this example, we'll leave the default values selected. Options include:

Missing data (see Missing Data Options):
 Error if missing data
 Exclude cases with missing data
 Use partial data  This is the default
 Imputation (replace missing values with estimates)

Algorithm:
 Batch  This is the default and is the only algorithm that can accommodate weights or missing values. Refer to the Technical Details section below.
 HartiganWong  Refer to kmeans for more information on this and the algorithms below
 Forgy
 Lloyd
 MacQueen

Output:
 Means
 Means table  Show the cluster means. Best if wanting to export to another program
 Segment profiling table  Show the composition of the Profiling variables within predicted clusters. More options to control the appearance are described here.
 Weight  Where a weight has been set for the output, the calibrated weight is used. See Weights in R.
 Cluster labels  An optional commaseparated list used to name the clusters predicted by the kmeans model
 Profiling variables  Select other variables or variable sets to crosstab with the segment cluster
5. Click the Calculate button (or tick the Automatic checkbox so that the analysis will rerun automatically if any changes are made).
Interpreting the Results
The standard table of means output shown above lists each of the clustering variables in the rows and shows the mean Top 2 Box percentage for each of the clusters.
 The size of each cluster (n) is shown in the column header.
 The red and blue highlights indicate whether or not the Top 2 Box score is higher (blue) or lower (red) than the overall mean. The red and blue colors are also scaled to provide some additional differentiation (darker shades of red/blue are farther from the mean).
 Means in bold font are significantly higher/lower than the mean score.
 The RSquared value shows proportion of variance in the cluster assignment that is explained by the each of the clustering variables. In the example above, we can see that there are 4 statements that have a greater impact on the segment/cluster predictions than do the remaining variables.
 The pvalue shows which statement variables are significant in the model.
 Where weights are provided, the percentages show weighted data but the n does not.
 The Variance Explained is a multivariate Rsquared statistic, which is sometimes known as omegasquared in the cluster analysis literature.
 The CalinksiHarabasz statistic can be useful when selecting the number of segments (higher is better), however, it should not be relied upon as the ultimate arbiter of number of segments as it is not particularly scientific.
See our Data Story Guide article Interpreting Cluster Analysis Outputs for more guidance on interpretation.
Saving Cluster Membership
Individual respondents can be assigned to the individual clusters in Displayr by first selecting the kMeans Cluster Analysis output and then selecting Inputs > Save Variable(s) > Cluster Membership.
See How to Save KMeans Cluster Membership for details.
Technical Details
The Batch algorithm works as follows:
 The HartiganWong kmeans algorithm is used to find clusters with missing data set to Exclude cases with missing data.
 Cases are assigned to the most similar cluster. Where Missing data is set to use partial data (the default), this means that cases that were ignored by HartiganWong are now included in the analysis.
 The cluster centers are updated. Where weights have been applied, this means that the cluster centers now reflect weights (they were ignored by HartiganWong).
 The previous two steps are repeated until the either the maximum number of iterations, iter.max has been exceeded (which defaults to 100), or, the OmegaSquared does not increase.
Acknowledgements
Uses the kmeans function from the stats R package.
See What is kMeans Cluster Analysis? and What is Cluster Analysis? for more information.
Next
How to Analyze Data by Groups/Segments
How to Do Latent Class Analysis
How to Create a Segmentation Comparison Table
How to Do Mixed Mode Cluster Analysis in Displayr
How to Save KMeans Cluster Membership
How to Do Hierarchical Cluster Analysis in Displayr