Short versions of two specific phobia measures: The snake and the spider questionnaires

Zoophobias are the most prevalent form of specific phobia worldwide. Two of the most widely used measures, the Snake Questionnaire (SNAQ) and Spider Questionnaire (SPQ) are good indicators of specific fears, but researchers have recognised that shorter, yet nevertheless reliable measures are needed. Hence the aims of this research were to develop short forms of the SNAQ and SPQ using item response theory and to use receiver operating characteristic (ROC) curve analyses to determine cut-offs for use in future research. Twelve-item versions of both scales (SNAQ-12 and SPQ-12) demonstrated excellent discrimination along the latent continuum in a sample of 1354 people. The SNAQ-12 and SPQ-12 showed excellent reliability and were highly correlated with the corresponding full-length scale. The scales discriminated between participants who reported snake (3.25%) or spider (8.05%) phobia and those who did not. Further analyses revealed that non-phobic women report higher fear of both snakes and spiders than do men, but this difference was not present in phobics. These findings suggest that the SNAQ-12 and SPQ-12 have considerable strengths, including shorter assessment and scoring times, whilst retaining high reliability and potential utility as a clinical screening tool.