This article describes the development and validation of a new observation instrument, the Scaffolding Observation Protocol for
Multilingual Learners (SCOPE-ML), designed to assess instructional changes resulting from two NPD projects at the University of Cincinnati. These projects focused on TESOL endorsement coursework and professional development for teachers of multilingual learners. The instrument was developed to measure differences in teaching practices between treatment and control groups in randomized controlled trials (RCTs), offering potential evidence of the effectiveness of the NPD interventions. The first project's treatment involved completion of the university's TESOL endorsement sequence, with participants recruited from upper elementary and secondary schools. The second project included two treatment conditions: (1) TESOL coursework and (2) completion of online modules with coaching and community of practice—with participants who taught in early elementary contexts.
Development of the SCOPE-ML followed a rigorous, rapid process—literature review, conceptualization, item drafting, revision, pilot testing, and initial research use—guided by a pedagogical stance grounded in scaffolding, understood as the systematic support of student learning through responsive, asset-oriented
instructional practice. This process produced evidence of high inter-rater reliability (percentage agreement and Cohen's kappa) and face validity (via peer debriefing and feedback). The study highlights the crucial role of teacher–student and peer interactions in fostering multilingual learners' literacy development and underscores the need for ongoing refinement of teaching practices for this population.