The foundational report produced by the National Research Council (NRC) that forms the basis for the NGSS. It calls for a new approach to science education based in scientific and educational research. The NGSS draws its content across the three dimensions, as well as the three-dimensional approach to learning, from The Framework.

Specify limits to large-scale assessment. They are not meant to put limits on what can be taught or how it is taught, but to provide guidance to assessment developers.

Grouping elements or concepts from multiple PEs in lessons, units, and/or assessments that students can develop and use together to build toward proficiency on a set of PEs in a coherent manner.

Supply examples or additional clarification and emphasis to the language of the performance expectations.

Coherence refers to conceptual building of knowledge and skills over the course of lessons, units, or years of instruction. This is in contrast to asking students to learn discrete pieces of content.

Found as part of the architecture of a standards page, these highlight some of the links between the listed PE and other NGSS PEs in the same and other grade bands as well as with CCSS ELA/Math standards. 


These are concepts that hold true across the natural and engineered world. Students can use them to make connections across seemingly disparate disciplines or situations, connect new learning to prior experiences, and more deeply engage with material across the other dimensions. The NGSS requires that students explicitly use their understanding of the CCCs to make sense of phenomena or solve problems.

Complete programs that comprehensively support the content goals of a science class over large pieces of instructional time (e.g., semesters, years). Curriculum includes all necessary components for instruction, such as lessons, assessment opportunities, and teacher guides.

The fundamental ideas that are necessary for understanding a given science discipline. The core ideas all have broad importance within or across science or engineering disciplines, provide a key tool for understanding or investigating complex ideas and solving problems, relate to societal or personal concerns, and can be taught over multiple grade levels at progressive levels of depth and complexity.

The bulleted practices, disciplinary core ideas, and crosscutting concepts that are articulated in the foundation boxes of the standards as well as the in the NGSS appendices on each dimension.

Formative assessment is a process used by teachers and students during instruction that provides feedback to adjust ongoing teaching and learning to improve students’ achievement of intended instructional outcomes.

Each performance expectation is three-dimensional, integrating elements from a practice, DCI, and CCC. These elements, which create the foundation for each PE, are listed in what are called foundation boxes underneath the PE in the architecture of the standards.

Grades 9-12

Instructional materials that are intended to guide teaching and learning for short term science goals. Lessons are not activities, but rather complete instructional pieces embedded within a unit, and include instructional supports, formative assessment opportunities, and coherent learning experiences for students.

Grades 6-8

The NGSS Network is a voluntary, informal network open to any state that adopts the performance expectations of the NGSS and seeks to improve K–12 science teaching and learning, using the NGSS as their foundation. As with development of the NGSS, Achieve coordinates the NGSS Network to meet the needs of states in implementing the standards, each state working on their own timetable and with their own priorities but sharing best practices and learning from one another in an effort to improve science education in their respective states.

The NGSS is not a set of daily standards, but a set of expectations for what students should be able to do by the end of instruction (years or grade-bands). So, the performance expectations set the learning goals for students, but do not describe how students get there.

Observable events that students can use the three dimensions to explain or make sense of.

The practices are what students DO to make sense of phenomena. They are both a set of skills and a set of knowledge to be internalized. The SEPs reflect the major practices that scientists and engineers use to investigate the world and design and build systems.

End of instruction goals or benchmarks for student proficiency.

Storylines are statements that describe the context and rationale for the Performance Expectations (PEs) in each grade band and section.

The goal of summative assessment is to evaluate student learning at the end of an instructional unit by comparing it against some standard or benchmark.

These are the three strands of knowledge and skills that students should explicitly be able to use to explain phenomena and design solutions to problems. The three dimensions are the Disciplinary Core Ideas (DCIs), Crosscutting Concepts (CCCs), and Science and Engineering Practices (“the Practices” or SEPs).

This is what students’ experiences in classrooms implementing the NGSS should reflect: developing and using elements of the three dimensions, together, purposefully (i.e., to explain phenomena or design solutions to problems). Lessons and units aligned to the standards should be three-dimensional; that is, they should allow students to actively engage with the practices and apply the crosscutting concepts to deepen their understanding of core ideas across science disciplines.

Instructional materials that include a series of lessons that, as a whole, are intended to give students coherent experiences that allow them to build toward a targeted set of content goals.