In an effort to enlarge the focus on teacher effectiveness to include environmental factors outside the classroom, this report investigated (1) the relationship between supervisors' ratings of teacher effectiveness and the ability of teacher interns to make instructional decisions conforming to the school's value and organizational structures and (2) characteristics differentiating teacher interns who can and cannot make such decisions. Data were collected on fifteen teacher interns in three organizationally differing schools through interviews, intern rankings, and three instruments designed to describe intern experience and establish meanings, patterns, and concepts for understanding intern adaptability in the school setting. Data interpretations are offered relating teacher effectiveness to the three organizational settings: traditional, magnet school, and Title I school. (MJB)