The NGSS have undergone numerous evolutions since their inception. Among the most powerful (and most recent) are the addition of evidence statements. The three dimensions—disciplinary core ideas, science and engineering practices, and crosscutting connections—already provide context for how students can demonstrate knowledge and how the performance expectation can be applied. The new evidence statements take this process a step further.
In an effort to describe more specifically what you would see in proficient student performance of the NGSS PEs, scientists and educators together developed Evidence Statements for every PE in every grade level. The evidence statements are intended to provide clear, measurable components that, if met, fully satisfy each PE described within the NGSS. (Next Generation Science Standards, 2015)
Evidence statements thus provide granularity to how students can demonstrate knowledge and application of the PE through evidence of learning.
It is important to note that the evidence statements do not represent the limit of a student’s learning, but rather minimum proficiency of the performance expectation. Similarly, they do not express the limits of what should be taught, nor are they a sequence of learning. Furthermore, demonstration of evidence statements is intended for use at the end of instruction—not during the instruction process (Next Generation Science Standards, 2015).
Evidence statements should be used for guidance on lesson design and assessment. Learning opportunities should provide students with hands-on experiences of phenomena that allow them to exemplify, use, and apply each evidence statement. However, NGSS clearly notes that evidence statements should not guide day-to-day instruction where it becomes a formulaic checklist of what students must learn that day:
Lesson-level goals (and indeed the lessons themselves) would still be three-dimensional (i.e., each contain a practice, a DCI, and a CCC), but they would likely engage students in many different practices along with a piece of the DCI(s) and CCC(s) under study. (Next Generation Science Standards, 2015)
Finally, evidence statements are not to be assessed individually:
Classroom instruction will often be focused on helping students build towards several different performance expectations at one time because so many concepts and practices are naturally interrelated. (Next Generation Science Standards, 2015)
Indeed, assessment and lessons should still rise organically from student interest, relevant anchoring/investigative/daily phenomena, and application of the three dimensions to real-world problems and the solutions designed for them.
Next Generation Science Standards. 2015. NGSS Evidence Statements. Retrieved from https://www.nextgenscience.org/sites/default/files/Front%20Matter%20Evidence%20Statements%20PDF%20Jan%202015_1.pdf