A student tells you that the narrator is unreliable and points to a line in the story. You ask how the line supports that reading, and the student reads it aloud again. That’s where I’d pause the lesson. The student has made a claim and found a relevant passage. Now they need to explain what the passage shows and why it matters.
The claim–evidence–reasoning framework, often shortened to CER, gives students a way to practise that last step. McNeill and Krajcik use the framework to teach scientific explanations. The activities below adapt the same structure for science, social studies, ELA, and checking AI-generated claims. McNeill and Krajcik on scientific explanations
What Goes in a Claim–Evidence–Reasoning Response?
| Part | What students do | Question to ask |
|---|---|---|
| Claim | Give a clear answer to the question. | What are you saying is true, likely, or supported? |
| Evidence | Select the data, source detail, or passage that bears on the claim. | What can a reader examine to check your answer? |
| Reasoning | Explain how the evidence supports the claim, using a relevant concept or principle. | What does the evidence show, and why does it matter here? |
1. Science — Explain a Pattern in the Data
Task. Give students this practice dataset from a model investigation. Two identical cups start with the same amount of water at the same temperature. One cup is wrapped in felt. After ten minutes, the wrapped cup’s water has cooled from 60°C to 54°C, and the unwrapped cup’s water has cooled from 60°C to 48°C. Ask which cup lost heat more slowly and how students know.
- Claim: The water in the felt-wrapped cup cooled more slowly during the ten-minute trial.
- Evidence: The wrapped cup’s water dropped by 6°C. The unwrapped cup’s water dropped by 12°C over the same period.
- Reasoning: Both cups began at the same temperature, so the smaller temperature drop over the same period shows slower cooling. Felt acts as insulation, which helps explain why energy transferred more slowly from the wrapped cup to its surroundings.
Copy-ready template
Under these conditions, _____.
Over _____, the measurements changed from _____ to _____ in one setup and from _____ to _____ in the other.
This pattern supports my claim because _____.
Follow-up. Ask what students would repeat or measure in another trial before drawing a broader conclusion.
Related: Classroom Essentials for Teachers
2. Social Studies — Read a Source for Perspective
Task. Give students two fictional sources from a town debate over closing a public market. A shopkeeper’s letter says families use the market to buy affordable food. A council memo discusses the cost of repairs and proposes closing the building. Ask what each source suggests the writer prioritized.
- Claim: The shopkeeper’s letter emphasizes families’ access to affordable food. The council memo emphasizes repair costs.
- Evidence: The letter refers to what families buy at the market. The memo links the proposed closure to the cost of repairing the building.
- Reasoning: The writers use different criteria to judge the same proposal. One focuses on what residents would lose, while the other focuses on what the town would have to spend. The documents support a claim about the writers’ stated priorities.
Copy-ready template
Source A emphasizes _____, while Source B emphasizes _____.
In Source A, the writer _____. In Source B, the writer _____.
These details reveal different priorities because _____.
To find out how other people saw the issue, I would look for _____.
3. ELA — Support an Interpretation of a Character
Task. Give students a short practice scene. Maya tells her friend she’s ready to perform. While waiting backstage, she grips her notes with both hands and asks twice when she has to go on. Ask what the scene suggests about how Maya feels.
- Claim: Maya is probably nervous about performing, even though she says she’s ready.
- Evidence: She grips her notes with both hands and asks twice when she has to go on.
- Reasoning: The repeated question suggests she’s preoccupied with when she’ll have to perform. Gripping her notes suggests physical tension. Taken together, those details make nervousness a plausible reading of her behaviour.
Copy-ready template
The scene suggests that _____.
One detail that supports this reading is _____. A second detail is _____.
Together, these details suggest _____ because _____.
Follow-up. Invite a second interpretation and ask students to decide which reading accounts for more of the scene.
4. AI Literacy — Check Whether a Chatbot’s Claim Fits the Source
Task. Give students a teacher-written example of a chatbot answer: “The school’s new phone rule improved grades.” Pair it with a fictional evaluation summary stating that teachers recorded fewer interruptions over four weeks and that grades were never collected. Ask students which part of the answer the summary supports.
- Claim: The evaluation supports a narrower statement about recorded classroom interruptions. It leaves the effect on grades unresolved.
- Evidence: Teachers recorded fewer interruptions during the four-week period. The evaluation did not collect grade data.
- Reasoning: Classroom interruptions and grades measure different outcomes. Evidence about one outcome leaves the other open. Fewer recorded interruptions after the rule also leaves room for other explanations.
- Revised statement: Teachers recorded fewer classroom interruptions during the four weeks after the new phone rule took effect.
Copy-ready template
The AI response claims _____.
The source reports _____. The outcome it actually measured was _____.
I judge the claim to be supported, partly supported, contradicted, or unverified because _____.
Based on the evidence, I would write _____.
A Quick Way to Teach the Reasoning Step
Put a claim and a piece of evidence on the board. Ask students to write the missing sentence that connects them. Compare two responses and ask which one explains the connection more clearly. For feedback, point to the part students can revise: narrow the claim, choose stronger evidence, or name the concept that explains why the evidence matters.
