Which data source is most informative for understanding whether an intervention's implementation varied across classrooms?

• A. Fidelity of implementation data
• B. Final exam scores only
• C. Classroom observation notes
• D. Attendance records

Answer: (C)

Data that describe actual classroom practice across settings are most informative for seeing whether an intervention was implemented differently from one classroom to another. Classroom observation notes provide a real-time, descriptive record of how the intervention is carried out in each room—the steps followed, pacing, use of materials, teacher prompts, and any adaptations or deviations. By examining these notes across classrooms, you can identify variations in how the intervention was applied, which helps explain differences in outcomes. In contrast, final exam scores reveal outcomes, not how the intervention was delivered; attendance records show presence but not implementation, and fidelity data, while useful, may be more structured and miss the broader contextual nuances captured in observation notes.