Both focus group discussions and information-choice questionnaires (ICQs) have previously been used to examine informed public opinions about carbon dioxide capture and storage (CCS). This paper presents an extensive experimental study to systematically examine and compare the quality of opinions created by these two research techniques. Depending on experimental condition, participants either participated in a focus group meeting or completed an ICQ. In both conditions participants received identical factual information about two specific CCS options. After having processed the information, they indicated their overall opinion about each CCS option. The quality of these opinions was determined by looking at three outcome-oriented indicators of opinion quality: consistency, stability, and confidence. Results for all three indicators showed that ICQs yielded higher-quality opinions than focus groups, but also that focus groups did not perform poor in this regard. Implications for the choice between focus group discussions and ICQs are discussed. (c) 2013 Elsevier Ltd. All rights reserved.