[Reliability and validity of a handedness questionnaire]

In this study, the validity and reliability of the hand preference item of a 13-item questionnaire adapted from Chapman and Chapman (1987) were investigated.

This questionnaire requires subjects to indicate which hand they usually use for various actions as follows: writing, drawing, throwing, using a hammer, using a toothbrush, using an eraser on paper, using scissors, holding a match when striking it, stirring a can of paint, using a spoon, using a screwdriver, twisting off the lid of a jar, and using a knife. Each item was scored as "1" for right, "2" for either, or "3" for left, and the handedness of subjects was scored from 13 (the strongest right-hand preference) to 39 (the strongest left-hand preference). In this study, 449 subjects filled in the questionnaire, and 43 subjects attended the test-retest study 3 weeks after the first examination. In order to determine the validity of the questionnaire, fine motor performance was measured using a finger tapping task, and the eye and foot preferences of the subjects were evaluated.

The test-retest reliability (r=.993) and internal consistency (Cronbach's Alpha=.97) were found to be high. In item-total score analysis, the best single item was "using a hammer", while the worst item was "twisting off the lid of a jar". Factor analysis yielded two factors, skilled and unskilled activities. Handedness scores were found to show a significant correlation with foot preference scores and the dominance score of the finger tapping task.

The results suggest that the handedness questionnaire is reliable and valid in measuring handedness.