Relationship between the harvard group scale of hypnotic susceptibility and the stanford hypnotic susceptibility scale: Form c

3 subgroups of 20 Ss with high, medium, or low scores on a slightly modified, tape-recorded version of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962) were later administered the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitzenhoffer and Hilgard (1962). HGSHSrA and SHSSrC correlated .59 which is lower than would be predicted by scale reliabilities. This, together with other data based on item characteristics, indicates that the 2 scales are not equivalent, but in part measure different aspects of hypnotic performance. Scores on HGSHSrA for low Ss are predictive of SHSS:C scores, but the stability of performance between HGSHS:A and SHSS:C is not as marked for medium and high Ss on HGSHS:A. This is partly a result of the failure of passive motor (primary) suggestibility to discriminate between levels of susceptibility, although challenge items do. The 2 clusters of items correlate .23 and .43 in HGSHS:A and SHSS:C respectively. The passive suggestibility items detract from the validity of the 2 scales.