Explores the role of research in the educational reform process by examining two research-informed professional development programs focusing on changing teachers' beliefs and practices. The Cognitively Guided Instruction program and the Integrating Mathematics Assessment projects provide contexts for examining the influence of teachers' knowledge…

Argues for a reconceptualization of teaching expertise based on psychological similarities of expert teachers to one another. The authors offer a prototype-based categorization model, drawn from psychological research, on which the family resemblance among expert teachers may be founded. The authors discuss several implications of the prototype…