Behavioral and subjective scoring of the Harvard group scale of hypnotic susceptibility: Further data and an extension

The present study replicated and extended Kirsch, Council, and Wickless's work evaluating the reliability and concurrent validity of a subjective response scale developed for the Harvard Group Scale of Hypnotic Susceptibility. Consistent with Kirsch et al.'s findings, the subjective counterpart of the Harvard scale demonstrated high reliability (coefficient .90) and concurrent validity (r = .84 with Harvard's standard behavioral score). Similar correlations of the behavioral and subjective scales with the Dissociative Experience Scale (DES) and Phenomenology of Consciousness Inventory (PCI) suggested that the two hypnotizability scales are measuring similar constructs. However, using the two scales in combination did not yield a morestringent measure of hypnotizability in terms of DES and PCI variables than using either of them alone.