This study is part of the on-going program evaluation of the Bill & Melinda Gates Foundation’s Model Schools Initiative and Model Districts Initiative in the state of Washington. In developing the Teaching Attributes Observation Protocol (TAOP) a conceptual framework was identified based on extensive literature on constructivist teaching. From this framework and the foundation’s written materials we identified important components and indicators of constructivist teaching and implications for the classroom. We then produced an observation protocol with 7 lesson components and a number of indicators under each component. The content validity of the instrument was then checked against the literature and existing observation instruments.