What is a CER?
A CER (Claim-Evidence-Reasoning) is a tool used in science classes to help students think critically and support their ideas. It is a three-step process that requires students to make a statement, provide evidence to support their statement, and explain the logic behind their statement. A claim is an opinion or idea about a scientific concept or phenomenon. The evidence is the data or research that supports the statement, and the logic is what connects the evidence to the statement. By using the CER tool, students can explain their scientific understanding and develop their critical thinking skills.
How is a CER used in science?
A CER is used to create a well-structured argument that answers a question about a scientific phenomenon. Students use this framework to write an argument when there is more than one possible claim or answer to a question. Therefore, because there is more than one answer, an argument is formulated to support one potential claim over the others.
Limitations of CER
I like to consider the CER a scaffold for the practice of argumentation. To make good arguments, students must understand the parts of an argument. And, this structure works well when arguments are written.
However, we also want our students to engage in verbal discourse in the classroom. In most cases, students won’t argue using the CER format during verbal discussions. Therefore, this is a helpful scaffold. But, ideally, this wouldn’t be the only way that argumentations would take place in the science classroom.
What benefits of Claim evidence reasoning?
It helps students align their conclusions to the purpose of the investigation, using their evidence to create reasoning that then provides direction for further investigation of the topic at hand.
Getting students to understand CER is important because it helps them think through the scientific process. All claims must have supporting evidence, and students should be able to explain the reasoning behind their thoughts. CER is science literacy for the win! CER can be applied to many different methods of teaching.
Creating CER Scenarios for Your Science Students: Step-by-Step
Step 1: Pick Your Topic
The first step is determining what topic you want students to investigate in your classroom. Ideally, this is related to your anchoring phenomenon in some way. However, if you haven’t developed extensive storylines yet, that’s okay. Start with a topic you want students to learn about. I like to write down the associated NGSS performance expectation.
Step 2: Come up with two (or more) potential claims.
Remember, you want your students to write an argument. Therefore, there must be more than one potential explanation. Otherwise, there isn’t an argument.
So, you need to come up with potential claims related to the argument. How do you do that?
Address student misconceptions with alternate claims.
I like to address student misconceptions about a topic. And luckily, there is a bank of students’ misconceptions for you to utilize. This is the CAST Item Specifications.
This resource is intended to help item writers for California’s state science test. However, it also includes student misconceptions about each performance expectation. Therefore, this is a great way to come up with alternate claims.
I STRONGLY suggest sticking to two potential claims, at least at first. Having at least two claims makes it possible for an argument to occur. However, more potential claims will lead to confusion. This is especially true when you introduce this skill. Later, once students have some practice, it’s possible to add additional claims.
Still, the best way to come up with alternate claims is from experience. As you get to know your student population, you’ll begin to recognize misconceptions that they have about different topics.
Step 3: Decide on an investigative phenomenon (or more than one).
Next, you’ll need investigative-level phenomena for students to investigate. These investigative pieces allow students to decide which claim is correct.
Ideally, these investigative phenomena you present lead to multiple pieces of evidence. These pieces of evidence support one or more of the claims. By giving students multiple pieces of evidence, you present students with the opportunity to sort the evidence. Then, they use the evidence to determine which claim is correct.
Step 4: Draft Your Storyline
Many teachers are intimidated by the term storyline. However, a storyline is just the order in which you present information to students. The storyline is well thought out so student understanding becomes clear over time.
Think about the order in which you will present the information. I like to move from simple to more complex. For example, I’d start the lesson sequence with things that are more directly observable. Asking students to observe the liquid coming from various beverages is VERY simple. (In fact, this might be too simple for your students!)
Then, I’d use the PhET simulation toward the end of the lesson sequence. Simulations are a great piece to add as an explanation tool if you follow the 5E model.
Step 5: Pick your CER scaffolds to teach students to use CERs to write arguments.
You’ve successfully set up your CER scenario. But, if you want to be truly successful, it’s important to plan scaffolds for your students. These scaffolds will look different depending on how much experience your students have with CER. If they have never used the CER framework, I highly recommend focusing ONLY on the claim and evidence for the first go-round.
