Editorial: Tools as a Catalyst for Practitioners' Thinking

The word tool has many different meanings. The definition perhaps most relevant to mathematics teacher education is “something (as an instrument or apparatus) used in performing an operation or necessary in the practice of a vocation or profession” (http://www.merriam-webster.com). Mathematics teacher educators use a variety of tools in both conducting research and supporting the preparation and professional development of teachers. In research, we use tools (e.g., observation protocols, assessment instruments, surveys) to collect data that will inform the question that is under investigation in a particular study or set of related studies. In designing and conducting professional education experiences for preservice and practicing teachers, we use tools to provide a scaffold for teacher learning–a structure that allows them to do something that would otherwise be challenging or even impossible to do (e.g., a guide for analyzing instructional tasks, a protocol for lesson planning, formative assessment lessons). Tools can also be used to communicate a standard or shared understanding of practice across the community of mathematics teacher educators, particularly practices that have been shown to support students' learning. According the National Academy of Education(1999, p. 35),