This study, conducted at a private STEM university in the Southeastern United States, presents a series of qualitative and quantitative data validating the Critical Teaching Behaviors Midterm Feedback Instrument (CTB-MFI). The instrument's validity and reliability were tested through a mixed-methods approach involving faculty surveys, statistical analyses, and a student experience survey and focus groups. A confirmatory factor analysis (CFA) suggests that the CTB-MFI model has excellent fit across multiple indicators, as well as excellent convergent validity. However, low discriminant validity indicates possible correlations between categories of critical teaching behaviors. Data further show that faculty and students perceive the instrument as valuable and easy to use: the CTB-MFI offers insightful midterm feedback, leading to improved teaching quality and student learning experiences. The CTB-MFI supports flexible use across various disciplines and provides a shared framework and language for discussing teaching effectiveness. This research offers valuable implications for educators, administrators, and researchers interested in improving learning outcomes and diversifying approaches to evaluating teaching effectiveness.