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Eberly College of Arts and Sciences


Social Work


Theoretical cluster analysis is used to sort out and organize the complex relations involved in empirically defining a sector. Cluster analysis is a quantitative technique to identify clusters of similar traits of empirical observations or cases. It is similar to factor analysis, except that the latter is ordinarily more concerned with identifying groups of related variables. The term Theoretical Cluster Analysis denotes a set of logical operations and arguments used to link the existing literature to questionnaire and scale items.

We begin by postulating a cluster of four sectors and four intersectors that together define the full extent of what has come to be known as the third sector and the entire social space that is “not-the-sector.” This approach makes use of a Venn diagram. This effort unfolded in a variety of separate steps: 1) Define a set of 20 clusters and group them into scales of five items each in order to provide an empirical measure for uniquely discriminating among four primary sectors (for which the labels of economy, polity, households and third sector are used). 2) Operationalize the five items of a commons (1992) as a set of Likert type measures. 3) Extract eight theoretical measures from a widely used definition of nonprofit organizations. 4) These clusters together were constituted as a set of Likert-type measures for the larger theoretical enterprise.