Item difficulty in childhood hypnotic susceptibility scales as a function of item wording, repetition, and age

Abstract

The Children's Hypnotic Susceptibility Scale (CHSS) of London (1963) and a revised version for children of the Stanford Hypnotic Susceptibility Scale, Form B (Rev. SHSS:B) were administered to a group of 26 children ranging in age from 8 to 16 years. This was part of a larger sample to whom the CHSS had been administered 3 years earlier. The comparison of the results of the 2 administrations of CHSS showed no significant differences in means (9.00, 9.19) or standard deviations (2.17, 2.87). The reliability was .72 (p = .001) when 3 atypically scoring Ss were eliminated. The item difliculties of eye closure and arm immobilization differed (p = .05) over the 2 administrations, both being more difficult at the earlier testing. It was suggested that these changes were a result of both practice and age effects. The comparison of the 2 different scales used at the latter testing (i.e., CHSS and Rev. SHSS:B) also showed no significant differences in mean scores (9.19, 8.85) or standard deviations (2.87, 2.81). The correlation between the 2 scales was .77 (p = .01). 3 items, eye closure, arm immobilization, and amnesia, snowed significant differences (p = .05) in the per cent passing the item, the first being less difficult on the Rev. SHSS:B, and the latter 2 being more difficult. Content and procedural differences were suggested to explain these obtained differences in item difficulties.