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How Claim, Evidence, Reasoning Works with NGSS Standards

Posted by Francis Vigeant on Sep 20, 2016

Updated on April 23rd, 2024.

When used in a Next Generation Science Standards (NGSS)-based classroom lesson, the Claim, Evidence, Reasoning (CER) Framework helps students summarize the results of their own science investigations within clear parameters. It simplifies the process of concluding scientific discovery: 

  1. Ask a question about real-world phenomena.

  2. Clearly state what you think is true.

  3. Describe why, backed up by the data and reasoning to support your claim. 

Enabling students to become scientists and engineers in the classroom requires more than simply giving them the opportunity to experiment with and build things. It requires teaching them the real-world practices (skills) that scientists, who discover knowledge, and engineers, who solve problems, use to answer questions and solve problems objectively.

These are vital skills that every student needs to engage the world around them and to succeed in the career or college of their choice.

Part of successfully instilling science and engineering mindsets into students is helping them to understand that the conclusions they come to at the end of a scientific experiment or an engineering design solution must be based not on hope, supposition, or clever rhetoric, but on objective evidence.

This is where Claim, Evidence, Reasoning (CER) model comes in, a model in which students offer claims about their hypothesis or prototype, using the evidence available from their experiment or prototype testing to support their reasoning, just as a scientist or engineer would.

Introducing CER to a Next Generation Science Classroom

To begin with, it’s important to understand that the Next Generation Science Standards require students to create, evaluate, and analyze simultaneously. This is made clear by including the science and engineering practices as one of the three dimensions of the NGSS. As a framework for hands-on science investigation, CER helps students lead this process every step of the way.

The science and engineering practices

In order to effectively work as scientists and engineers, students must develop the critical thinking skills needed  to extend their current knowledge to solve problems and answer questions. Asking questions about science phenomena can feel overwhelming to students at first, and the CER method gives them simple steps to ask and answer these questions effectively – just like a scientist or engineer would. 

Using the CER model, students learn to question the world around them and build hands-on investigations into science phenomena that help them better understand it. They collect and analyze data, work in small groups to back up their claims using reasoning skills and their current knowledge, and practice how to communicate these findings with their peers. The CER Framework is a simple but effective guide students can use to help collect and evaluate new information throughout their lives.

Students identify and solve problems.

CER and NGSS Scientific and Engineering Processes (SEP)

As students engage in the science and engineering practices, they are actively creating, analyzing, and evaluating. The CER Framework helps conclude scientific and engineering processes the same way that scientists and engineers do – leading their own investigations into real-world phenomena that end with a strong evidence based conclusion that they can share with the class and back-up with clear evidence and reasoning.  

Scientific and engineering processes


As we let students take the lead in the classroom, , it is important they follow a framework like CER that helps them move logically from asking a question to presenting  an evidence-based conclusion. With clear learning frameworks in place, students are free to engage creatively with the phenomena and think critically about the data they collect. 

One thing to remember is that both science and engineering processes can be nonlinear and include repeated iterations based on evidence. Learning from our mistakes involves going back to re-evaluate our hypothesis, evidence, and claims – an important lesson! These processes do, however, provide direction and a logical, forward momentum.

Using the Claim, Evidence, Reasoning Model with NGSS

When applying the Claim, Evidence, Reasoning model during a Next Generation Science Standards classroom lesson, the final step of both scientific and engineering processes is simplified for our student-scientists. That’s because they understand how their critical thinking and hands-on investigation links directly to forming a conclusion.

Compare this to following a step-by-step guide for a science experiment without first understanding why you are doing it, or what you are trying to learn from it. Data without context is confusing and difficult to shape using our own knowledge and reasoning skills. When students use the CER Framework with NGSS, they will be able to form a conclusion the way professionals do, provided they are also the ones asking the questions, designing the experiments, and forming the conclusions. CER helps simplify that final process into manageable steps that result in an evidence based conclusion.

The claim-evidence-reasoning model comes in the final step of both the scientific and engineering processes—forming a conclusion.

How the CER model fits into the science and engineering processes 

The CER model is a useful tool for students to use to  learn how to construct an explanation to a question about a phenomena.. Applying the CER model to a science classroom helps students craft:

  • A claim about their hypothesis (or prototype) that answers a question or solves a problem.

  • Evidence resulting from the student’s investigative data.

  • Reasoning involving a scientific principle that describes why the evidence supports the claim.

When students develop a conclusion using the CER model, they are taking the data they've obtained, evaluating it, and communicating their results in a persuasive argument to their peers that answers their initial question or provides the solution to the initial problem. Students don’t receive better grades for conclusions that found a hypothesis is supported (true) or not supported by the evidence gathered, students receive high marks for accurately engaging in the process of using evidence to support a claim regardless of the concussion the evidence points to.

Students use these practices as they create their conclusion. 

The Claim, Evidence, Reasoning model provides students with an objective, scientific structure to support the development of a conclusion. It helps students link their conclusion back  to the original purpose of the investigation, using evidence backed by their own reasoning, and providing them with direction for further investigation into the topic at hand.

Topics: Next Generation Science Standards

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