This paper focuses on current policy and best practices in science education. The development of national science standards followed a different developmental pathway as compared to the development of the Common Core State Standards (CCSS). Two major guiding documents have guided the National Research Council and state-level efforts to reform science and engineering education. Specifically, the National Research Council constructed a Framework for K–12 Science Education; the Framework described what it means to be proficient in science and explained the interrelationships among inquiry practices, cross-disciplinary science and engineering concepts and disciplinary core ideas. The Next Generation Science Standards (NGSS) was developed by a state-level effort to develop educational standards consistent with the content and structure of the Framework. This paper describes a recently developed instrument known as the Systematic Characterization of Inquiry Instruction in Early LearNing Classroom Environments (SCIIENCE). The SCIIENCE instrument allows researchers and educators to determine how well teacher practice in early childhood classrooms aligns with the Framework. The strengths of the SCIIENCE instrument include (a) objective descriptions of specific instructional classroom practices, (b) the ability to document changes in teacher practice that occur in response to NGSS-aligned professional development, (c) the ability to incorporate results into professional development and teacher evaluation, and (d) the utility of the instrument for future research.