Measuring scientific classroom discourse: The <i><scp>DiISC</scp> Version 2.0</i>'s validity and use in observing secondary science lessons

Abstract To continue to support long‐term, ongoing science curriculum and instruction reform efforts in the United States, there is a significant need to be able to reliably measure teachers’ discourse‐rich, inquiry‐based instruction. In this external validation study, we present the Discourse in Inquiry Science Classrooms Version 2.0 (DiISC 2.0) as a valuable observational instrument for researchers to investigate multiple aspects of science teachers' lessons. The DiISC 2.0 is grounded in a researchbased conceptual framework of a scientific classroom discourse community, focused on fundamental socioconstructivist characteristics of lessons, including scientific inquiry, oral and written discourse, and academic language development. We collected and analyzed new data from 807 science lessons to develop and expand the instrument's original validity argument beyond the associated professional development program for broader use. We determined the DiISC's factor structure and examined its correlation with the Electronic Quality of Inquiry Protocol . Finally, some items that did not represent DiISC constructs were removed. Thus, the DiISC 2.0 instrument can be used to measure students’ opportunities to learn science and provide feedback to teachers on their progress toward building an inclusive scientific classroom discourse community for all students, in particular, historically marginalized groups and multilingual learners.