Trace a claim to evidence, inspect how the evidence was produced, and record limits before relying on it.
Field diagramA question becomes a test
Estimated reading
10 min
Estimated practice
20 min
Equipment
Web access or a supplied packet of sources; a comparison table.
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Objective
By the end, you can:
Separate a source's claim, method, result, and interpretation.
Check whether a source is appropriate for the question.
Record provenance, date, and limitations without treating authority as proof.
Read the chain, not just the headline
A source is useful when you can trace a claim to an observation or analysis and understand the conditions around it. Start by copying the claim in your own words, then find the population or material studied, the comparison, the outcome definition, and the design. A review can orient you to a field, a primary study can show how a particular result was produced, and a standard or manufacturer method can define a measurement procedure. These roles are different; none makes a source automatically correct.
Ask whether the evidence can answer the claim. An association in an observational study does not by itself show that an intervention caused an outcome. A result in one material or instrument range may not transfer to yours. Peer review is a useful signal of scrutiny, but it does not replace reading the methods, checking whether the numbers are presented accurately, and looking for replication or competing evidence.
Authority: who produced it, and what expertise or responsibility do they have?
Fit: does the method measure the quantity or population in your question?
Transparency: can you locate methods, data, uncertainty, and conflicts?
Independence: could funding, selection, or incentives shape the claim?
Currency: has later work changed the context or found limits?
Build an evidence note
For each important source, record title, organization or authors, date, stable URL or identifier, claim supported, design, key limitation, and the exact place you checked. Preserve the source's wording only as a short quotation when necessary; your note should explain why it matters to your question. A confident source with a mismatched method is weaker evidence than a modest source that directly measures the relevant quantity.
Use at least one source that describes the method and one that represents the wider evidence when a claim is consequential.
Treat preprints, promotional pages, anecdotes, and single studies as evidence with different constraints, not as interchangeable proof.
When sources disagree, compare populations, methods, outcomes, dates, and uncertainty before choosing a side.
Worked example
A careful source note
Claim: a particular measuring vessel gives more repeatable water volumes than a cup. The student finds a teaching method, a manufacturer specification, and a general chemistry text.
01Method source: describes eye-level reading and vessel calibration; supports technique, not a universal tolerance.
02Specification: identifies the vessel's class and stated tolerance; supports a conditional equipment claim.
03Text: explains repeatability and accuracy; supports definitions, not this vessel's performance.
04Conclusion: use the vessel for a defined volume when its stated specification fits the question; verify actual performance when accuracy matters.
Materials
Set out what you need.
Three sources selected from the NIH and National Academies links below, or another clearly identified source set
Evidence-note worksheet
Safety & stop conditions
Pause if the work no longer fits the plan.
Do not use a web source as a substitute for a current safety data sheet, institutional procedure, or qualified supervision. Health, legal, and safety decisions require current authoritative guidance.
Method
Work through the steps.
01
State the claim
Write the claim as a testable sentence and list the decision it might influence.
02
Trace the evidence
Locate the method, sample or material, comparison, outcome, and analysis; mark anything missing.
03
Write the limitation
Name one reason the result might not apply to your context and one piece of evidence that would reduce that uncertainty.
Checkpoints
Observe, record, investigate.
Your note identifies the source type and its role.
The claim is narrower than or equal to the evidence supporting it.
A reader could retrieve the same source from your citation.
Common mistakes
Correct the process, preserve the record.
Treating a citation count or polished website as evidence of method quality.
Inspect the design, data, and fit to the question; popularity is not validation.
Reading only an abstract or headline.
Check the methods, outcome definition, exclusions, and limitations before relying on the result.
Choosing only sources that agree.
Search for boundary conditions, null findings, and independent work, then record disagreements.
Practice
Source triage
Use the NIH trustworthiness page and NIH rigor page linked below as two agency sources, then select one primary paper or official method source on a question you care about. Compare what each source actually measured; no special source packet is required.
Which source gives the most direct method detail?
What claim is the least supported by the available evidence?
Write a two-sentence evidence note that preserves a limitation.
01Why can a peer-reviewed study still be a poor source for your question?
Answer: Its population, material, outcome, or method may not match your target. Peer review indicates scrutiny, not automatic transferability.
02What should an evidence note preserve besides the URL?
Answer: The claim, source type, date, method or evidence checked, relevant limitation, and enough citation detail for retrieval. URLs can change and a bare link hides reasoning.
03A company page reports a test with no sample size or method. How should you use it?
Answer: Treat it as a lead or statement of the company's claim, not as independent evidence. Seek the underlying method and a suitable independent or authoritative source before relying on it.
