Handedness scale: how many and which items?

A stepwise analysis of the Cronbach Alpha Coefficient (CAC) was performed on five large samples of adults and young children, in order to choose the ''minimum'' set of items of a handedness scale which gives the maximum reliability. In adults, a handedness scale with 12 items has nearly the same or even a better CAC than other scales with more items; so, a choice of 10 to 12 items seems to be adequate. For children, a scale with eight items seems to be quite reliable but it is not impossible that a scale including more items would lead to a slight increase of CAC. The controversial usefulness of a precise assessment of the ''general handedness factor'' (the first principal component) generated by handedness questionnaires and its J-shaped distribution in the general population are discussed.