On the objectivity of the scoring of Harvard Group Scale of Hypnotic Susceptibility

The authors analyzed the Harvard Group Scale of Hypnotic Susceptibility, Form A, scores of 1,887 subjects. In addition to the usual self-scoring, trained observers also scored the behavioral manifestations of the subjects according to the same standardized criteria during the sessions. Self- and observer-scoring proved to be internally consistent and highly correlated (r = .832). Item-by-item analysis, however, yielded notable differences. Subjects and observers scored items differently in about 20% of the cases; only 3 items showed no systematic bias toward pass or fail. Many subjects' hypnotizability level would be classified differently according to observer categorization (Cohen's Kappa = .563). We suggest reconsidering the "objectivity" of self-scoring.