Both focus group discussions and information-choice questionnaires (ICQs) have previously been used toexamine informed public opinions about carbon dioxide capture and storage (CCS). This paper presentsan extensive experimental study to systematically examine and compare the quality of opinions createdby these two research techniques. Depending on experimental condition, participants either participatedin a focus group meeting or completed an ICQ. In both conditions participants received identical factualinformation about two specific CCS options. After having processed the information, they indicated theiroverall opinion about each CCS option. The quality of these opinions was determined by looking at threeoutcome-oriented indicators of opinion quality: consistency, stability, and confidence. Results for allthree indicators showed that ICQs yielded higher-quality opinions than focus groups, but also that focusgroups did not perform poor in this regard. Implications for the choice between focus group discussionsand ICQs are discussed.