Evidence Statements Help Make Learning Visible

January 30, 2024

It surprises many educators that the Performance Expectations of the Next Generation Science Standards (NGSS) do not include expectations for what to teach or for how students demonstrate proficiency. Without this guidance, teachers may feel lost and unsure about how to teach or assess student learning. The “Evidence Statements,” released two years after the standards, are a game-changer.

In this blog, we’ll highlight the Evidence Statements.  We will show how they are the answer for assessing growth and grade-level proficiency in the three dimensions of science learning.  In summary, the Evidence Statements articulate observable and measurable knowledge and skills students should demonstrate to satisfy the NGSS Performance Expectations.  

To see how educators might use the Evidence Statements, let’s consider Ms. Lee. Ms. Lee is a high school science teacher embarking on the process of implementing a new NGSS-aligned curriculum. For years, she’s taught a unit called “Chemical Reactions and Stoichiometry.” During the unit, students defined what a reaction is, represented reactions with chemical symbols, and balanced chemical equations. Students conduct and classify four chemical reactions at the end of the unit. They share their results on a poster. If you were to ask her students what they learned in the unit, they’d likely respond, “We learned about chemical reactions and stoichiometry.” If you asked them why, they might say, “To make our poster!” Certainly, making a poster isn’t the intended learning we want students to walk away with!

In preparation for her weekly meeting with her coach, Ms. Lee reviews her new curriculum to plan for an NGSS-aligned unit on chemical reactions. She’s a bit perplexed by the unit title: “Why does bread dough rise when I leave it on the counter?” She starts by reading the performance expectations connected to Chemical Reactions. The first Performance Expectation reads, “Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties” (HS-PS1-2). Right away, she’s concerned. The science vocabulary is missing. It lacks words and phrases like  “stoichiometry” and “balancing chemical equations.” How is she supposed to know if a student is showing proficiency with that standard?  Don’t they need vocabulary and content knowledge?

The next day, Ms. Lee is meeting with her instructional coach. Ms. Lee poses the question of missing vocabulary to her coach. Ms. Lee’s coach explains that this omission doesn’t mean the writers of the NGSS don’t value these concepts. Instead, omitting vocabulary checklists reflects the shift in the goal of these new standards. The NGSS Performance Expectations focus on broader concepts. They connect core ideas with Crosscutting Concepts through Science and Engineering Practices. They rely on educators to do the work of specifying necessary vocabulary.

Ms. Lee confesses, “But that doesn’t help me with what students need to know or be able to do to meet these standards. I don’t know how to teach students about bread dough to learn science. I’m so confused!”

Her coach responds. “You’re right. These standards are different. So, we need to go one step further in our analysis. We must dive into the relevant Evidence Statement for this Performance Expectation.” 

Together, they navigate to the page for HS-PS1-2 on the NGSS website. On the right side of the screen, under the “Related Evidence Statements” heading, they click on “HS-PS1-2-1 Evidence Statements.”




This action opens a .pdf file.  They scroll to the bottom of this file.  Her coach points out that the Evidence Statements are the “observable features of the student performance by the end of the course.” 

Ms. Lee sees that these items include naming some of the concepts she’d initially expected but could not locate in the Performance Expectations.

From there, Ms. Lee and her coach unpack the relationship between “bread dough rising” and the scientific knowledge necessary to explain it. Students need to learn about the numbers of atoms, types of bonds, how bonds form, and other technical aspects of chemical reactions. They have to explore patterns of reactivity and valence electrons as well. Rather than being an end unto itself, the newly acquired learning will be in service of explaining the phenomenon.

Ms. Lee leaves the meeting ready to dig deeper into the unit. This approach is new and different from how she learned (and has been teaching for years). However, the evidence statements provide her with more clarity about why the standards changed in the first place. Students now learn the “why” and “how” instead of just the “what.” This is exciting because it invites real-world application of scientific principles. Ms. Lee understands that this will take time to get used to. But at the end of the unit, her students will be more fluent in big-picture science ideas. They will be able to say, “We learned how to write and balance chemical equations to explain the dough rising phenomenon.” 

This view may counter old standards and textbooks. They focused on facts and figures. They relied on students to make broad connections and understand big ideas to apply in various situations. The design of the NGSS provides teachers and curriculum designers freedom. They can choose what specific phenomenon and content will allow students to internalize big ideas and be ready for new situations. It opens the door for curiosity, questions, critical thinking, and authentic engagement. And isn’t that what science is ultimately about?


Ready to bring GLEAM science instruction to life?

UnboundEd strives to support educators in providing grade-level, engaging, affirming, and meaningful (GLEAM) science instruction. This type of instruction gives students access to rich and authentic opportunities to do and learn science.  Looking for more information on GLEAM science instruction? Check out some of our previous posts. In our last post, we outlined the organization of the Disciplinary Core Ideas (DCIs) and Performance Expectations.

Are you a science educator or school leader looking to increase student engagement and success with science? Join us at Standards Institute or a Summit, and please share this blog with other science educators in your orbit!