According to teachers, their student teaching experience is generally the most powerful and beneficial experience in their preparation. While all student teaching experiences are not created equal, understanding and measuring how they are different turns out to be a challenge.

New research from Robert Vagi, Margarita Pivovarova, and Wendy Barnard digs into data from student teachers at one large institution, finding that yes, there was significant variation in how quickly the student teachers improved throughout their year-long experience, but no, nothing to definitively explain it. Factors such as student teacher GPA, age, and ethnicity had some relationship with improvements in classroom observation scores over the course of the year, but they only explained about 1 percent of the variation.

We have a reasonable theory. The NCTQ Teacher Prep Review has long documented the wide variation of student teaching program quality. In particular, few teacher preparation programs (13 percent) require that their teacher candidates are assigned only to classrooms taught by effective teachers—disappointing considering the evidence that who serves as the cooperating teacher is a make-or-break factor for student teaching.

We suspect (and suspect the researchers would agree) that the key missing data point in the study was a measure of the quality of the cooperating teachers. Co-teaching with and observing an effective teacher in the classroom is a sure way to support student teachers of all differing characteristics in improving their skills.