CER (Claim, Evidence, Reasoning)

CER (Claim, Evidence, Reasoning) is an approach to teaching students to think and write scientifically. It helps students connect their conclusions to the purpose of the investigation and develops their reasoning skills.

CER can be used in a variety of ways and is particularly helpful when implementing it into labs. There are many NSTA ADI (argument driven inquiry) books that follow this format and provide great ideas for science labs.


CER stands for claim, evidence, and reasoning, a framework that allows students to make scientific explanations. It starts with a question posed by the teacher or based on a lab experience, and then explains the answer in three parts: the claim, the evidence, and the reasoning.

The claim is the most important part of any science explanation or question, and it should be the shortest sentence possible. It should not start with a yes or no, and should clearly state what will be investigated and the results of that investigation.

The evidence is the data or information used to support the claim, and this can be quantitative (numerical) or qualitive. The reasoning is the logical connection between the evidence and the claim, and it should include at least one scientific principle that is applicable to both. The best claims are the ones that make the most sense to the reader, and the most well-rounded explanations incorporate all of these elements.


The evidence that cer stands for is the data that students gather during an experiment, watch a demo or simply observe. This can be quantitative or qualitative, depending on the question and lab.

It is important for students to only use the data that directly supports their claim or explanation. This is the evidence that will help them write their CER response.

The CER framework is a great way to give students the skills they need to make better explanations for scientific phenomena. It makes explicit the three parts of making an explanation: a claim, evidence, and reasoning.


Claim, Evidence, Reasoning (CER) is a framework used to answer questions and give explanations. CER is a great way to strengthen students’ analysis and writing skills as they explore scientific phenomena.

It’s also a great way to teach argumentative reasoning in the classroom. The reasoning piece explains “how” or “why” the evidence supports the claim.

Often, this is the most difficult part for students to write – they struggle to tie their evidence and claim together scientifically.

Teaching students the seven simple steps to break down a CER and guide them through answering science questions using this format will help them build their confidence as they master this skill. They will also start to see the time it takes to write a CER decrease as they practice over and over again.


The CER (claim, evidence, reasoning) inquiry process is a powerful learning strategy that students can practice in their science lessons. This involves posing a question or an observation to the students, asking them to write out a claim and provide evidence to support their answer and then explaining their reasoning behind the claim.

The claims they make should be well-thought out and backed by relevant evidence, such as a data table or graph. The evidence they provide should also be backed up by a solid reasoning explanation.

CER is a powerful learning strategy that students can use in their science lessons to help them understand what they are discovering and explain why it matters. The CER (claim, evidence, reasoning) strategy is aligned with the Next Generation Science Standards and helps students connect their findings to the purpose of their investigations.

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