Measurement of handedness via self-report: the relationship between brief and extended inventories.

Three self-report measures of handedness were explored. For simple dichotomous classification into right- versus left-handed groups, a brief (4-item) and an extended (12-item) inventory produced 98.8% classification concordance in a sample of 250 subjects. When handedness was treated as a continuous variable, indexes based upon the short and expanded scales correlated highly (r = 0.95). A single-item handedness measure was also created which produced handedness classifications which were better than 97% concordant with the brief and extended handedness scales for dichotomous classification. The methodological implications of these findings for handedness measurement are discussed.