Avoiding the effect of item wording by means of bipolar instead of unipolar items: An application to social optimism

Abstract

Scales including positively and negatively worded items usually show an impaired degree of homogeneity. The transformation of unipolar positively and negatively worded items into bipolar items can avoid this disadvantageous effect. The precondition for this transformation is that each pair of items refers to the same topic. It is this topic that serves as the heading of the bipolar item. This scale construction method is demonstrated in the items of the social optimism scale (Schweizer & Schneider, 1997) that comprises unipolar items. The investigation of both the original and the transformed scales in a sample of 808 participants revealed equivalence and a high quality for both scales. Results of an additional sample confirmed the validity of both social optimism scales. Copyright © 2009 John Wiley & Sons, Ltd.