This Microsoft Excel 97 (or later) spreadsheet will compute an individual's score on the Dissociative Experiences Scale (DES) and also the person's probability of being a "dissociative type."

Niels Waller and his coauthors have used statistical methods to determine that scores on the Dissociative Experiences Scale (DES) may cause researchers to overestimate the percentage of their sample that has a dissociative disorder. According to these authors, "normal dissociation" (such as the capacity for imaginative absorption) exists on a continuum within the general population, but "pathological dissociation" does not. In their reasoning, pathological dissociation is a class variable; either a person is a pathological dissociator, or a person is not; there is no continuum. The "dissociative type" of person is described by Waller and associates as a member of the dissociative taxon.

Waller's articles provide a method (and the statistical justification for that method) to calculate the probability that a person is a member of the dissociative taxon. The calculation is elaborate. One of the article on the DES taxon provides an SAS computer program for doing the calculations, and Darryl Perry has kindly translated that program into an Excel spreadsheet for wider accessibility.

The spreadsheet is in the public domain, and may be distributed free of charge, according to Darryl Perry, so long as he is credited with its construction. Go to the DES Taxon calculator when you click here.

ISSTD does not warrant the accuracy of its calculations, but we have tried it out using the sample data in The prevalence and biometric structure of pathological dissociation in the general population: Taxometric and behavior genetic findings (Waller and Ross, 1997) and we arrived at the same results as listed in the article. ISSTD does not provide technical support for this spreadsheet.

Thanks to Peter Barach, PhD for writing this material and providing the forms for posting.