Designing Science Inquiry: Claim + Evidence + Reasoning = Explanation

 Science is a dynamic and ever-evolving field that has shaped our understanding of the world around us. At its core, science is not just about facts and data; it's a process of inquiry and discovery. In this article, we will explore the framework of Claim, Evidence, and Reasoning (CER) as a fundamental approach to designing science inquiry and arriving at explanations that withstand scrutiny.

Understanding the CER Framework

The Claim, Evidence, and Reasoning framework is a structured approach to scientific investigation. It provides a clear path for students and scientists to formulate and test hypotheses, collect and analyze data, and arrive at evidence-based conclusions. This framework is a powerful tool for guiding scientific inquiry and ensuring that explanations are grounded in evidence and sound reasoning.


A claim is a statement or assertion about a phenomenon, event, or relationship between variables. It is what you believe to be true based on your observations and data. Claims are the core of scientific explanations because they express the conclusions or hypotheses that scientists seek to support or refute.

For example, if you were conducting an experiment to investigate whether increased exposure to sunlight affects plant growth, your claim might be, "Increased exposure to sunlight positively impacts plant growth."


Evidence is the data, facts, and observations that support or refute a claim. It serves as the foundation upon which the claim is built. Evidence can take various forms, including quantitative data, qualitative observations, measurements, and experimental results.

In the plant growth experiment, your evidence might consist of measurements of plant height, the number of leaves, and the overall health of the plants in varying levels of sunlight exposure.


Reasoning is the logical and scientific thinking that connects the evidence to the claim. It explains how the evidence supports the claim and why it is a valid conclusion. Reasoning involves critical thinking and making explicit the logic behind the claim.

In the plant growth experiment, your reasoning might include an explanation of photosynthesis, which is the biological process that enables plants to convert sunlight into energy for growth. You would explain how the increased exposure to sunlight leads to more energy production and, in turn, greater plant growth.


The explanation is the final product of the CER framework. It is a comprehensive and well-structured presentation of the claim, evidence, and reasoning. A well-crafted explanation not only conveys the results of the investigation but also offers insights into the underlying science.

In our example, the explanation would summarize the claim, present the evidence (e.g., data tables and graphs), and provide a detailed reasoning section that connects the claim to the evidence. The explanation should also acknowledge potential sources of error and limitations in the study.

Designing Science Inquiry Using CER

To design a scientific inquiry using the CER framework, follow these steps:

Identify a Question or Phenomenon: Start by identifying a question or phenomenon you want to investigate. This becomes the basis for your claim.

Formulate a Claim: Create a clear and concise statement that answers the question or addresses the phenomenon. Your claim should be testable and specific.

Collect Evidence: Design and conduct experiments or gather data that can be used to support or refute your claim. Ensure that your data is relevant and reliable.

Analyze the Data: Use appropriate methods to analyze your data, such as statistical tests or graphical representations.

Construct Reasoning: Develop a logical and scientific reasoning that explains how the evidence supports the claim. This step involves demonstrating an understanding of relevant scientific principles.

Compose the Explanation: Combine your claim, evidence, and reasoning into a well-structured explanation. The explanation should be clear, coherent, and accessible to others.

Peer Review and Revision: Share your explanation with peers or mentors and be open to feedback. Revise your explanation based on their input.

Refine the Experiment: If necessary, modify your experimental design, data collection methods, or analysis to address any shortcomings or uncertainties identified during the peer review process.

Final Explanation: Produce a final, polished explanation that represents your scientific inquiry accurately.

Frequently Asked Questions (FAQs)

1. Why is the CER framework important in science?

The CER framework is crucial in science because it provides a systematic approach to conducting scientific investigations and arriving at evidence-based explanations. It helps ensure that scientific claims are supported by relevant and reliable evidence and that the reasoning is sound. This enhances the credibility and rigor of scientific research.

2. Can the CER framework be used in all scientific disciplines?

Yes, the CER framework can be applied in various scientific disciplines, including biology, chemistry, physics, earth science, and environmental science. It is a versatile approach that can be tailored to suit the specific needs and methods of different scientific investigations.

3. How can teachers use the CER framework in the classroom?

Educators can use the CER framework to teach students the process of scientific inquiry and critical thinking. By presenting students with questions or phenomena and guiding them through the steps of formulating claims, collecting evidence, and constructing reasoning, teachers can help students develop a deeper understanding of scientific concepts and the scientific method.

4. What is the difference between a claim and a hypothesis?

A claim is a statement or assertion about a phenomenon, event, or relationship between variables that is believed to be true based on evidence. A hypothesis, on the other hand, is a specific, testable prediction that suggests an outcome or relationship in an experiment. Hypotheses are often used to generate claims, which are broader and more general.

5. Is the CER framework limited to the classroom, or is it used in real scientific research?

The CER framework is not limited to the classroom; it is used in real scientific research as well. Scientists follow a similar process of formulating claims, gathering evidence, and constructing reasoning to arrive at explanations in their research. The framework helps ensure that scientific findings are credible and can withstand scrutiny in the scientific community.

6. How does the CER framework help students develop critical thinking skills?

The CER framework encourages students to think critically by requiring them to evaluate evidence and construct sound reasoning to support their claims. It promotes the use of data and logical thinking to arrive at explanations, fostering a deeper understanding of scientific concepts and the scientific method.


The Claim, Evidence, and Reasoning (CER) framework is a powerful tool for designing and conducting scientific inquiries that lead to evidence-based explanations. Whether in the classroom or the laboratory, this structured approach helps ensure that scientific claims are well-supported by relevant evidence and sound reasoning. By following the steps of the CER framework, students and scientists can not only arrive at meaningful explanations but also contribute to the ongoing advancement of scientific knowledge.

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