Core Idea
Definition
CER organizes an argument into a claim, the evidence supporting that claim, and the reasoning that explains why the evidence justifies the conclusion.
In Plain English
Say what you think, show what supports it, and explain why that support actually matters.
Framework Structure
Components
Flow
State claim -> Present evidence -> Explain the link between evidence and claim
How to Apply
- 1.Write the claim as a direct answer to the question at hand
- 2.Choose evidence that is relevant rather than merely impressive
- 3.Explain the reasoning that links the evidence to the claim
- 4.Remove unrelated facts that do not strengthen the argument
- 5.Check whether the reasoning would still seem valid to someone who disagrees
When to Use
- •Short analytical writing and explanation
- •Teaching and learning environments
- •Feedback, review, or recommendation memos
- •Arguments that need clarity more than formal complexity
- •Any context where evidence-backed explanation matters
When NOT to Use
- •When the issue requires richer handling of qualifiers and rebuttals
- •When there is no meaningful evidence yet and the goal is exploration
- •When the conversation is mainly relational or strategic rather than explanatory
- •When the framework is used to flatten complex uncertainty into overconfidence
Example
Problem
A student or analyst must explain whether a product launch underperformed because of pricing.
Application
- 1.Claim: pricing was a major contributor to underperformance
- 2.Evidence: conversion dropped most in the most price-sensitive segments after the change
- 3.Reasoning: if price resistance increased after the pricing shift and the effect concentrates in sensitive segments, pricing is a plausible driver
Conclusion
The explanation becomes clearer because the relationship between evidence and conclusion is explicit.
Takeaway
CER is simple, but it still forces the crucial move from assertion to justified explanation.
Common Mistakes
- •Asserting a claim with weak or irrelevant evidence
- •Listing evidence without explaining why it supports the conclusion
- •Confusing more evidence with better evidence
- •Using reasoning that merely restates the claim
- •Ignoring counterevidence that narrows the claim
How to Practice
one sentence claim
Force the claim into one sentence so the argument has a clear center.
why this evidence
After listing evidence, add one sentence explaining why it should move a reasonable reader.
support pruning
Delete facts that are interesting but do not materially strengthen the claim.
Related Cognitive Biases
confirmation bias
People often choose evidence that flatters the claim without testing whether it truly supports it.
illusion of explanatory depth
A person may believe they have explained a claim when they have only restated it.
availability bias
Vivid evidence can crowd out more representative evidence.
Related Frameworks
Related Skills
Variants & Extensions
Typical Failure Modes
- •Weak evidence
- •Missing reasoning link
- •Assertion disguised as support
Further Reading
- They Say / I Say by Gerald Graff and Cathy Birkenstein
- A Rulebook for Arguments by Anthony Weston
- Thank You for Arguing by Jay Heinrichs