Consensus that current teacher evaluation systems often do little to help teachers improve or to support personnel decision making has led to a range of new approaches to teacher evaluation. This brief looks at the available research about teacher evaluation strategies and their impacts on teaching and learning.

Prominent among these new approaches are value-added models (VAM) for examining changes in student test scores over time. These models control for prior scores and some student characteristics known to be related to achievement when looking at score gains. When linked to individual teachers, they are sometimes promoted as measuring teacher ―effectiveness.‖

Drawing this conclusion, however, assumes that student learning is measured well by a given test, is influenced by the teacher alone, and is independent of other aspects of the classroom context. Because these assumptions are problematic, researchers have documented problems with value-added models as measures of teachers‘ effectiveness. These include the facts that:

1. Value-Added Models of Teacher Effectiveness Are Highly Unstable: Teachers‘ ratings differ substantially from class to class and from year to year, as well as from one test to the next.

2. Teachers’ Value-Added Ratings Are Significantly Affected by Differences in the Students Who Are Assigned to Them: Even when models try to control for prior achievement and student demographic variables, teachers are advantaged or disadvantaged based on the students they teach. In particular, teachers with large numbers of new English learners and others with special needs have been found to show lower gains than the same teachers when they are teaching other students.

3. Value-Added Ratings Cannot Disentangle the Many Influences on Student Progress: Many other home, school, and student factors influence student learning gains, and these matter more than the individual teacher in explaining changes in scores.

Other tools have been found to be more stable. Some have been found both to predict teacher effectiveness and to help improve teachers’ practice. These include:

• Performance assessments for licensure and advanced certification that are based on professional teaching standards, such as National Board Certification and beginning teacher performance assessments in states like California and Connecticut.
• On-the-job evaluation tools that include structured observations, classroom artifacts, analysis of student learning, and frequent feedback based on professional standards.

  In addition to the use of well-grounded instruments, research has found benefits of systems that recognize teacher collaboration, which supports greater student learning.

  Finally, systems are found to be more effective when they ensure that evaluators are well-trained, evaluation and feedback are frequent, mentoring and coaching are available, and processes, such as Peer Assistance and Review systems, are in place to support due process and timely decision making by an appropriate body. 

  And here is a short summary of the report by Linda Darling-Hammond.