One of the biggest jobs of any leader is to help drive continual improvement within his/her institution. In US education they have decided that continual improvement should be done through teacher evaluation; even though the research on teacher evaluation has not demonstrated that is leads to improvement in instructional practices. According to Weisberg, Sexton, Mulhern, and Keeling (2009) teacher evaluation does not recognize good teaching, leaves poor teaching unaddressed, and does not inform decision-making in any meaningful way. In addition Duffett, Farkas, Rotherham, and Silva (2008) state that three of four teachers report that their evaluation process has virtually no impact on their classroom practice. Together you have a fairly serious argument for ditching teacher evaluation as a method for school improvement. When 75% of teachers state that evaluation doesn't impact their teaching, but this is the approved method the government wants to use to improve education, something is rotten in the state of educational research. Clearly we need to do something differently in order to improve student learning, and possibly that something different is to focus on learning, not teaching. The April 2013 issue of Educational Leadership is focused on the role of the principal and the articles have some excellent research based approaches and strategies for the improvement of student learning and institutional improvement.
Duffett, A., Farkas, S., Rotherham, A. J., & Silva, E. (2008). Waiting to be won over: Teacher speak on the profession, unions, and reform. Washington, DC: Educational Sector.
Weisberg, D., Sexton, S., Mulhern, J., & Keeling, D. (2009). The widget effect: Our national failure to recognize differences in teacher effectiveness. New York: New Teacher Project.