Argument repertoire as a reliable and valid measure of opinion quality: Electronic dialogue during campaign 2000

A new measure of opinion quality that we name "argument repertoire" (AR) is introduced and evaluated. AR refers to the relevant reasons that one has for one's own opinions and the relevant reasons that others with opposite opinions might have. The measure is shown to be reliable and to have construct validity. Those with elevated AR also were more likely to attend on-line deliberative groups during the presidential election and to contribute to those conversations. Those who participated in on-line deliberations tended to have higher AR scores on particular issues that were discussed. The role of AR in deliberative political groups is explored.