Multiple threats to validity and reliability exist when value-added models (VAMs) rely wholly on standardized assessments to measure the relationship between teachers and their K-12 students' learning gains. Research on a curriculum-based VAM, built on evidence-based practices, continues to establish an explicit link between teacher candidates' instruction and their K-12 students' learning gains. Statistical tests of association were used to analyze measures of student learning and university supervisors' ratings during classroom observations with a department instrument, the Narrative Observation Scale. Results from a sample of 23 teacher candidates revealed that (a) two measures of student learning were related and attributed to candidates' instruction, and (b) 67.6% of the variance in the percentage of K-12 students meeting their specific learning objectives was accounted for by the teacher candidates' mastery of specific classroom management behaviors. Limitations and directions for future research are discussed regarding continued efforts to refine a rational, curriculum-based VAM.