How to Read the Next Generation Science Standards

The Next Generation Science Standards (NGSS) are distinct from prior science standards in three essential ways.

1) Performance. Prior standards documents listed what students should "know" or "understand." These ideas needed to be translated into performances that could be assessed to determine whether or not students met the standards. Different interpretations sometimes resulted in assessments that were not aligned with curriculum and instruction. The Next Generation Science Standards have avoided this difficulty by developing performance expectations that state what students should be able to do in order to demonstrate that they have met the standard, thus providing the same clear and specific targets for curriculum, instruction, and assessment.

2) Foundations. Each performance expectation incorporates all three dimensions from the National Research Council report A Framework for K-12 Science Education (Framework)—a science or engineering practice, a core disciplinary idea, and a crosscutting concept.

3) Coherence. Each set of performance expectations lists connections to other ideas within the disciplines of science and engineering and with Common Core State Standards in English Language Arts/Literacy and Mathematics.

These three unique characteristics are embodied in the format of the standards, beginning with the "system architecture."

System Architecture

As shown in the illustration, each set of performance expectations has a title. Below the title is a box containing performance expectations. Below that are three foundation boxes, which list (from left to right) the specific science and engineering practices, disciplinary core ideas, and crosscutting concepts that were combined to produce the performance expectations above. The bottom section lists connections to other related disciplinary core ideas at the same grade level, to related disciplinary core ideas for younger and older students, and to related Common State Standards in English Language Arts/Literacy and Mathematics. These sections are further described below.

Performance Expectations

Performance expectations are the assessable statements of what students should know and be able to do. Some states consider these performance expectations alone to be "the standards," while other states also include the content of the three foundation boxes and connections to be included in "the standard." The writing team is neutral on that issue. The essential point is that all students should be held accountable for demonstrating their achievement of all performance expectations, which are written to allow for multiple means of assessment.

The last sentence in the above paragraph—that all students should be held accountable for demonstrating their achievement of all performance expectations—deserves special attention because it is a fundamental departure from prior standards documents, especially at the high school level where it has become customary for students to take courses in some but not all science disciplines. The Next Generation Science Standards take the position that a scientifically literate person understands and is able to apply core ideas in each of the major science disciplines, and that they gain experience in the practices of science and engineering and in crosscutting concepts. In order for this to be feasible, the writing team has limited the core ideas included in the performance expectations to just those listed in the Framework.

The Next Generation Science Standards writers initially attempted to include all of the disciplinary core ideas from the Framework verbatim in the performance expectations, but found that the resulting statements were bulky and reduced readers’ comprehension of the standards. Instead, the performance expectations were written to communicate a "big idea" that combined content from the three foundation boxes. In the final phase of development, the writers, with input from the state teams, further limited the number of performance expectations to ensure that this set of performance expectations is achievable at some reasonable level of proficiency by the vast majority of students.

Some states have standards that include concepts that are not found in the Next Generation Science Standards. However, in most cases not all students in those states are expected to take courses in all three areas of science and engineering. The Next Generation Science Standards are for all students, and all students are expected to achieve proficiency with respect to all of the performance expectations in the Next Generation Science Standards.

A second essential point is that the Next Generation Science Standards performance expectations should not limit the curriculum. Students interested in pursuing science further (through Advanced Placement or other advanced courses) should have the opportunity to do so. The Next Generation Science Standards performance expectations provide a foundation for rigorous advanced courses in science or engineering that some students may choose to take.

A third point is that the performance expectations are not a set of instructional or assessment tasks. They are statements of what students should be able to do after instruction. Decisions on how best to help students meet these performance expectations are left to states, districts, and teachers.

In the example, notice how the performance expectation combines the skills and ideas that students need to learn, while it suggests ways of assessing whether or not second graders have the capabilities and understandings specified in the three foundation boxes.

As shown in the example, most of the performance expectations are followed by one or two additional statements in smaller type. These include clarification statements, which supply examples or additional clarification to the performance expectations; and assessment boundary statements, which specify the limits to large scale assessment.

Notice that one of the disciplinary core ideas was "moved from K-2." That means the writing team decided that a disciplinary core ideas that the Framework specified for the end of second grade could be more easily assessed if combined with the other ideas specified for third grade. This was done only in a limited number of cases.

Also, notice that the code for this performance expectation (3-LS4-1) is indicated in each of the three foundation boxes to illustrate the specific science and engineering practices, disciplinary core ideas, and crosscutting concepts on which it is built. Because most of the standards have several performance expectations, the codes make it easy to see how the information in the foundation boxes is used to construct each performance expectation.

The codes for the performance expectations were derived from the Framework. As with the titles, the first digit indicates a grade within K-5, or specifies MS (middle school) or HS (high school). The next alpha-numeric code specifies the discipline, core idea and sub-idea. All of these codes are shown in the table below, derived from the Framework. Finally, the number at the end of each code indicates the order in which that statement appeared as a disciplinary core idea in the Framework.

Foundation Boxes

While the performance expectations can stand alone, a more coherent and complete view of what students should be able to do comes when the performance expectations are viewed in tandem with the contents of the foundation boxes that lie just below the performance expectations. These three boxes include the science and engineering practices, disciplinary core ideas, and crosscutting concepts, derived from the Framework, that were used to construct this set of performance expectations.

Disciplinary Core Ideas. The orange box in the middle includes statements that are taken from the Framework about the most essential ideas in the major science disciplines that all students should understand during 13 years of school. Including these detailed statements was very helpful to the Next Generation Science Standards writing team as they analyzed and "unpacked" the disciplinary core ideas and sub-ideas to reach a level that describes what each student should understand about each sub-idea at the end of grades 2, 5, 8, and 12. Although they appear in paragraph form in the Framework, here they are bulleted to be certain that each statement is distinct.

Science and Engineering Practices. The blue box on the left includes just the science and engineering practices used to construct the performance expectations in the box above. These statements are derived from and grouped by the eight categories detailed in the Framework to further explain the science and engineering practices important to emphasize in each grade band. Most sets of performance expectations emphasize only a few of the practice categories; however, all practices are emphasized within a grade band. Teachers should be encouraged to utilize several practices in any instruction, and need not be limited by the performance expectation, which is only intended to guide assessment.

Crosscutting Concepts. The green box on the right includes statements derived from the Framework’s list of crosscutting concepts, which apply to one or more of the performance expectations in the box above. Most sets of performance expectations limit the number of crosscutting concepts so as to focus on those that are readily apparent when considering the disciplinary core ideas. However all are emphasized within a grade band. Again, the list is not exhaustive nor is it intended to limit instruction. Aspects of the Nature of Science relevant to the standard are also listed in this box, as are the interdependence of science and engineering, and the influence of engineering, technology, and science on society and the natural world. Although these are not crosscutting concepts in the same sense as the others, they are best taught and assessed in the context of specific science ideas, so they are also listed in this box.

Connection Boxes

Three Connection Boxes, below the Foundation Boxes, are designed to support a coherent vision of the standards by showing how the performance expectations in each standard connect to other performance expectations in science, as well as to Common Core State Standards. The connections are grouped into three sections:

Connections to other disciplinary core ideas in this grade level. This box lists the disciplinary core ideas that connect a given performance expectation to material covered at the same grade level but outside the presented sets of performance expectations. For example, both physical sciences and life sciences performance expectations contain core ideas related to photosynthesis and could be taught in relation to one another. Ideas within the same main disciplinary core idea as the performance expectation (e.g., PS1.C for HS-PS1-1) are not included in the connection box, nor are ideas within the same topic arrangement as a performance expectation (e.g., HS.ESS2.B for HS-ESS1-6).

Articulation of disciplinary core ideas across grade levels. This box lists disciplinary core ideas that either (1) provide a foundation for student understanding of the core ideas in a given performance expectation (usually at prior grade levels) or (2) build on the foundation provided by the core ideas in this performance expectations (usually at subsequent grade levels).

Connections to the Common Core State Standards. This box lists pre-requisite or connected Common Core State Standards in English Language Arts/ Literacy and Mathematics that align to given performance expectations. For example, performance expectations that require student use of exponential notation will align to the corresponding Common Core State Standards for Mathematics standards. An effort has been made to ensure that the mathematical skills that students need for science were taught in a previous year where possible. Italicized performance expectation names indicate that the Common Core State Standards is not pre-requisite knowledge, but could be connected to that performance expectation.

Alternative Organizations of the Standards

The organization of the Next Generation Science Standards is based on the core ideas in the major fields of natural science from the Framework, plus one set of performance expectations for engineering. The Framework lists 11 core ideas, four in life sciences, four in physical sciences, and three in Earth and space sciences. The core ideas are divided into a total of 39 sub-ideas, and each sub-idea is elaborated in a list of what students should understand about that sub-idea at the end of grades 2, 5, 8, and 12. These grade-specific statements are called disciplinary core ideas. The standards arranged by disciplinary core ideas precisely follow the organization of the Framework.

At the beginning of the process of developing the Next Generation Science Standards, the writers examined all of the disciplinary core ideas in the Framework to eliminate redundant statements, find natural connections among disciplinary core ideas, and develop performance expectations that were appropriate for different grade levels. The result was a topical arrangement of disciplinary core ideas that usually, but not always correspond to the arrangement of core ideas identified in the Framework. This structure underlies the standards arranged by topic. The coding structure of individual performance expectations in the topical arrangement of standards is based on the same one that applies to the disciplinary core ideas in the Framework. Due to the fact that the Next Generation Science Standards progress toward end-of-high-school core ideas, individual performance expectations may be rearranged in any order within a grade band.