Tuesday, January 30, 2018

Graphing Cluster Output (SPSS)

The single most endearing aspect of creating cluster models, is the beautiful and eclectic graphs that can be generated from the systemic output. The methodology that is illustrated in this example can be utilized for any cluster model, it is not simply limited to Two Step Cluster Analysis.

We will be using the data that was generated from our prior example.


To begin, select “Graphs” from the topmost menu, then select “Chart Builder”.

This should generate the following interface.

From this interface, select “Scatter/Dot” from the “Gallery” option. Drag the variable “Two Step Cluster Number” to the upper right corner of the illustration so that it rests in the box labeled “Set color”. You may drag whatever variables you wish to the left and bottom of the example graph. These variables will represent the X and Y axis of your graphical output.

The initial output will resemble:

Double click on the graphic to enable a customization menu.

In the “Chart Editor” menu, click on the circle to the left of “1”, this will launch an additional menu.

From this menu, by changing the colors of “Fill” and “Border”, you can increase the readability of your output.

We will perform the same step for the variable “1” within the legend.

The final product will resemble the image below.

Typically, if the model is created with care, and is of high “Cluster Quality”, the graphical output will resemble something such as:

Image Source: https://en.wikipedia.org/wiki/Cluster_analysis

In the next article, we will discussing the SPSS function: “Descriptives”. The utilization of this function is necessary for the creation of K-Means Clusters, which which be the topic of the subsequent article.

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