Claim-Evidence-Reasoning
Class Size
Individual
Time
15-25 min
Technology
None
Domain
Cognitive
Difficulty
Intermediate
Delivery
Face-to-Face, Online, Hybrid
Overview
Claim-Evidence-Reasoning (CER) is a framework for scientific argumentation. Students make a Claim (the answer to a question), provide Evidence (data from the investigation), and explain the Reasoning (how the evidence supports the claim using scientific principles).
Educational Purpose
Students often state conclusions without evidence or reasoning. CER provides a structure that ensures every conclusion is backed by data and scientific principles. This develops scientific thinking and argumentation skills.
Educational Psychology Behind It
Research on argumentation in science (Berland & Reiser, 2009) shows that structured argumentation improves understanding of scientific concepts and the nature of science. The CER framework makes the structure explicit.
Why It Works
Research on argumentation in science (Berland & Reiser, 2009) shows that structured argumentation improves understanding of scientific concepts and the nature of science. The CER framework makes the structure explicit.
When to Use It
Use after any investigation, demonstration, or data analysis in Science. Also works in English for argumentative writing. Grade 5 and up. Takes 15-25 minutes. Provide sentence frames for scaffolding.
When NOT to Use It
Avoid accepting claims without evidence or evidence without reasoning. Avoid CER for purely factual questions. Do not use CER only for formal assessments -- it is a thinking tool, not just a writing format.
Best Grade Levels
Grades Grade 5 to Grade 12
Best Subjects
Science, English
Step-by-Step Classroom Guide
- 1After an investigation, pose a question: What can we conclude from our data?
- 2Claim: Students state their answer as a clear claim.
- 3Evidence: Students cite specific data from the investigation that supports the claim.
- 4Reasoning: Students explain why the evidence supports the claim using scientific principles.
- 5Review: Is the claim clear? Is the evidence specific? Is the reasoning scientific?
- 6Share and discuss: Compare CER responses. Which are most convincing? Why?
Classroom Scenario
Mr. Dela Cruz has Grade 8 students investigate whether ice melts faster in fresh water or salt water. After the experiment, students write CER responses. Claim: 'Ice melts faster in fresh water than in salt water.' Evidence: 'The ice in fresh water melted in 12 minutes; the ice in salt water took 18 minutes.' Reasoning: 'Salt water has a lower freezing point, which means it can absorb more heat before the ice melts. The salt disrupts the hydrogen bonds, making it harder for the ice to absorb heat from the surrounding water.' The CER structure makes the student's thinking visible and assessable.
Sample Dialogue
Advantages
- Develops scientific argumentation and thinking
- Provides a clear structure for conclusions
- Makes thinking visible for assessment
- Works with any investigation or data
- Prevents unsupported conclusions
Limitations
- Students struggle with the reasoning component initially
- Requires understanding of scientific principles for reasoning
- Can become formulaic without genuine argumentation
- Assessing reasoning requires content expertise
Common Mistakes
- Accepting claims without evidence or reasoning
- Not providing sentence frames for scaffolding
- Using CER only for formal assessment instead of as a thinking tool
- Not discussing and comparing CER responses
Variations & Adaptations
Adapt the investigation complexity, equipment needs, and group structures based on students' lab experience and safety considerations.
Technology Integration
This strategy requires no technology. If desired, enhance with digital tools such as Google Docs for collaborative writing or Padlet for sharing responses.
Assessment Ideas
Assess through observation of participation, quality of science, and formative checks such as exit tickets or quick writes.
Reflection Questions
🤔 What did you learn from this activity?
🤔 What was the most challenging part?
🤔 How could you use this strategy in a different subject?
🤔 What would you do differently next time?
References & Further Reading
- Berland, L. & Reiser, B. (2009). Making Sense of Argumentation and Explanation. Science Education, 93(1).