DCIs, SEPs, and CCs, Oh My! Understanding the Three Dimensions of the NGSS

Abstract

The Next Generation Science Standards' three dimensions--disciplinary core ideas (DCIs), science and engineering practices (SEPs), and crosscutting concepts (CCs)--were headliners at NSTA's national conference in Chicago and featured in many of the organization's other professional-development efforts this year (NGSS Lead States 2013). To some, the idea of DCIs, SEPs, and CCs may seem obvious and not all that new (Figure 1, p. 68). Haven't we been doing science inquiry since the release of the National Science Education Standards (NSES) in 1996? What is new and different about the NGSS, and what do these three dimensions mean for curriculum, instruction, and assessment? [ILLUSTRATION OMITTED] There are, in fact, several major differences in how the new standards portray science education. These differences call for substantial shifts in terms of our learning goals, instructional strategies, and assessment. In the next sections, we highlight what is new and different about each dimension. We do not address explicitly intertwining the three dimensions; a forthcoming article will discuss their integration. Much of what we discuss below draws directly from A Framework for K--12 Science Education (NRC 2012), which guided the development of the NGSS and is the foundation for the new standards. While the NGSS do provide some information from the Framework (in the blue, orange, and green boxes; see Figure 1) to elaborate on the performance expectations, these are only snippets of the more elaborate descriptions found in the Framework. We therefore urge readers to turn to the Framework when trying to understand the three dimensions and the standards. DCIs There are DCIs for each of the four major disciplines: physical sciences, life sciences, Earth and space sciences, and engineering (engineering, technology, and applications of science). Each of these disciplines includes no more than four DCIs, reflecting a concerted effort to cull the numerous ideas that all students are expected to know. While there are somewhat fewer ideas to teach, each is complex, with ample depth to delve into over the course of schooling. To rise to the level of a DCI, an idea must meet four criteria. First, it must be a key organizing principle within the discipline or across several disciplines; that is, it should be a core idea in the eyes of scientists. Second, it must have broad explanatory power: It should help learners understand and be able to reason about an array of phenomena and problems in the discipline. In this sense, it needs to be a useful thinking tool that is generative for students, and it should help them think about phenomena and problems they may encounter in and out of the classroom, both now and in their future. Third, a DCI needs to be relevant and meaningful for students. It should relate to phenomena and problems that students find intriguing. Fourth, the idea needs to have depth that allows for continued learning over the course of schooling. There are two complementary implications of this last point. First, the DCI, in some basic form, must be accessible to young learners, and, second, it must have enough complexity that it can be unpacked and deepened in higher grades. Many of the concepts (e.g., ionic bonds, mitochondria) and even topics (e.g., volcanoes, taxonomy) currently taught in school do not meet these criteria. As educators, it is incumbent upon us to closely evaluate what we are teaching and to dramatically prune the unwieldy tree of concepts we try to cover. Taken together, the DCIs create a conceptual toolkit that students can use to reason about and explain phenomena. The focus on explaining phenomena represents an important shift in the goals of instruction. Rather than teaching ideas in the abstract or in isolation, the new aim is to engage students in using these ideas to explain interesting phenomena. For example, instead of having students describe the water cycle and its components, students should be explaining cloud formation or precipitation patterns by using understandings about the water cycle and thermal-energy transfer to describe how weather events come about. …