Cross-Checking Evidence with Claim, Evidence, Reasoning

By Better Wise

You already know how to trace a claim back to its primary source. What you still need is a container for what you find: a written paragraph that separates the claim, the evidence, and the reasoning linking them, so that someone who does not trust you can check your work without asking you questions. That container is the Claim, Evidence, Reasoning structure (CER), and it is the difference between "I read somewhere that..." and a paragraph a skeptical editor would let through.

By the end of this lesson you can:

• Write a claim-evidence-reasoning paragraph that another person can check without asking you for clarification.
• Tell two genuinely independent sources from one origin wearing two hats.
• Test a single paragraph against two independent sources and record where they agree, disagree, or stay silent.

The three parts, and the job each one does

Claim: one sentence you could prove wrong

A claim is not a topic and not a mood. It is a single sentence that could, in principle, be shown false. "Screen time is harmful" is a feeling. "Among the 13-to-15-year-olds surveyed, more hours of self-reported social media use went with higher self-reported anxiety scores" is a claim: it names a group, a measure, and a relationship, and it stops at association instead of sneaking in causation.

Evidence: specific enough that a stranger could check it

Evidence is the material another person can go and look at. It needs a named source, a date, a number with its unit, and ideally a pointer to the primary document. "Studies show" and "experts agree" are not evidence; they are placeholders where evidence should be. Two sources are _____ when neither derives its information from the other. And evidence you cannot trace to a _____ is still a rumor with good posture.

Reasoning: the bridge you have to build yourself

The _____ sentence explains why this evidence supports that claim, and how far it goes. Most weak arguments collapse here, not at the evidence stage. A number can be perfectly accurate and still be stretched into a conclusion it cannot carry.

Tip: Read your reasoning sentence out loud and ask: "Could a different explanation produce the same evidence?" If yes, the reasoning has to say so, and the claim has to shrink.

Exercise 1. Label each sentence as claim (C), evidence (E), or reasoning (R). (a) "Routes with more than 30 stops run later on average." (b) "A 2023 audit of 40 city bus routes found average delays of 7 minutes on high-stop routes compared with 3 minutes elsewhere." (c) "That fits, because every extra stop adds boarding time, and boarding time compounds along a route."

Click to reveal the answer

(a) C, (b) E, (c) R. Note the trap in (c): "every extra stop adds boarding time" is itself an added claim, so a careful writer either cites evidence for it or hedges with "plausibly, because."

Two sources, or one source wearing two hats

Cross-checking only works when the second source is independent. A hundred articles citing the same press release is one source counted a hundred times. That is circular reporting, and it is the most common way careful people get fooled, because repetition feels like confirmation. When sources split, the honest move is to _____.

Three questions that expose a shared origin:

• Does this piece link to a primary document, or only to another article?
• Do both sources quote the same number, to the same decimal, in the same phrasing?
• Do both trace back to one company, one funder, or one preprint?

Exercise 2. Which pairs are independent? (a) A university press release and the journal article it summarizes. (b) Two newspapers, where the second cites the first. (c) A randomized trial by team A and an independent replication by team B. (d) Two articles quoting the same industry-funded report.

Click to reveal the answer

Only (c). In (a) both share one origin, in (b) the second is downstream of the first, and (d) is one origin with two narrators. Treat each of those as a single data point.

Running a cross-check in five moves

flowchart TD
    C["📝<br/>Write the CER paragraph"]
    T["🔍<br/>Trace each evidence item to its origin"]
    S["🧾<br/>Find a second independent source"]
    K["⚖️<br/>Compare: agree, disagree, silent"]
    R["✏️<br/>Revise the claim to fit"]
    C --> T --> S --> K --> R
    K -->|"not independent"| S
    R -->|"claim outruns evidence"| C

Compare along three lines: agreement (rare and worth noting), disagreement (check whether the two are even measuring the same thing), and silence. Silence is underrated: if source B never mentions what source A is shouting about, that absence is information.

Here is the whole move on a realistic claim. "The city's four-day week pilot raised output by 20 percent."

1. Trace the 20 percent: it appears in a council press release, sourced to an internal survey of 12 managers, with no published data.
2. Look for a second source: a regional news site reports the same 20 percent, quoting the same press release. Not independent.
3. Find a genuinely separate source: an independent evaluation of similar pilots elsewhere reports mixed results, with gains concentrated in teams that also cut meeting load.
4. Revise: "In one city pilot, managers self-reported a 20 percent output gain; independent evaluations of similar pilots find gains mainly where teams also reduced meeting time."

Exercise 3. The evidence says two of five participants improved. The claim says "The program works." Rewrite the claim so it matches the evidence, and add one reasoning sentence.

Click to reveal a model answer

Claim: "Two of five participants improved on the measured outcome." Reasoning: "With five participants and no comparison group, that result is consistent with the program helping, but also with normal variation, so it cannot support a general claim that the program works."

Rules of thumb from the verification desk

• Write the reasoning sentence first. Then go find evidence. Building the bridge before the cargo exposes what you actually believe, and where confirmation bias will push you.
• Count origins, not articles. Two clicks upward will usually tell you whether you have two sources or one.
• Let scope drift set off alarms. Watch for a claim that loses a condition in transit: "effective for adults with mild symptoms" becomes "effective."
• Keep a "what would change my mind" line. If you cannot name it, you have a belief, not a finding.
• Do not confuse a confident voice with evidence. Confidence is a tone, not a citation.

What to carry forward

CER gives you three separate places to fail, which is the point: a fuzzy claim, an untraceable source, and a bridge that never got built each look different once written down. Write the paragraph, count origins instead of headlines, and let the weaker claim win when the two sources split.

Next, you will point this same structure at a harder target: confident, fluent, AI-generated answers that cite sources which may not exist.

Front: What are the three parts of a CER paragraph? Back: Claim, evidence, reasoning.

Front: What makes a sentence a usable claim? Back: It is specific and could in principle be shown false.

Front: Why is 'studies show' not evidence? Back: It names no source, date, or document that a reader could check.

Front: What job does the reasoning sentence do? Back: It explains why this evidence supports that claim and how far it goes.

Front: When are two sources independent? Back: When neither derives its information from the other.

Front: What is circular reporting? Back: Many outlets repeating one origin, so one source appears to be many.

Front: What does shared origin look like in practice? Back: Same numbers, same decimal, same phrasing, or both citing one press release or preprint.

Front: Why does silence count in a cross-check? Back: A second source not mentioning the claim is itself information about how established it is.

Front: What is scope drift? Back: A claim losing its conditions in transit, such as 'effective for adults with mild symptoms' becoming 'effective'.

Front: What should you do when two independent sources disagree? Back: Shrink or qualify the claim so it matches the weaker, better-supported version.

Front: Which part should you write first, and why? Back: The reasoning, because it exposes what you already believe before you go looking for evidence.

Front: What is the 'what would change my mind' line for? Back: It separates a checkable finding from a belief you are protecting.

Front: How do you confirm a source is primary? Back: Trace it to the original document, dataset, or recording rather than another article about it.

Field Notes from the Fact-Check Desk

• Write the reasoning before the evidence. If you draft the reasoning sentence first and it feels uncomfortable, that discomfort is the useful part. It tells you which belief you were about to defend.
• Do not let one source wear a disguise. Before you count a second source, ask what it read. Two articles that quote the same preprint, the same press release, or the same anonymous official are one source with two logos.
• Name the direction of the evidence. "Supports" and "proves" are not synonyms. Most good reasoning sentences include a limit: supports under these conditions, for this group, at this scale.
• Keep a line you cannot delete. Write down in advance what evidence would make you drop the claim. A cross-check without that line drifts into a search for confirmation.
• Shrink instead of shouting. When sources disagree, the honest move is almost never "they are lying" and almost never "both are right". It is a smaller claim that both sources can carry.

Quick recall drill before you move on:

In the _____ sentence you state what is being asserted, in one sentence, with its scope intact. The _____ sentence names a specific, checkable finding and where it came from. The _____ sentence explains why that finding supports that claim, and how far. Two sources are independent only when neither _____. When independent sources disagree, the calibrated move is to _____ until it matches the best-supported version.

What to Carry Forward

• A claim-evidence-reasoning paragraph is three sentences, and the third one is where most weak arguments fall apart.
• Cross-checking is not counting links. It is asking whether the second source has its own eyes on the world.
• Disagreement between good sources is normal; it usually means the claim needs a narrower shape, not a louder voice.
• The habit to keep: state the claim, name the evidence, explain the link, then write the line that would change your mind.

Next, we point this same toolkit at a source that never cites anything and always sounds certain: the AI-generated answer, and how to audit it line by line.