For experts18 min read · Intermediate · Updated Sep 2026

Choosing sources that hold up

A contribution is only as strong as the source behind it. Editors accept quickly when the source is primary, current, says exactly what you claim, and opens at the right place. This guide covers how to find that source, test it, and cite it so the check takes seconds.

Primaryclosest to the evidence

Currentnot superseded

Preciseopens at the right place

1The source ladder

Sources sit on a ladder. The higher the rung, the faster an editor can accept on the source alone.

Primary

Original research, official statistics, the current guideline, the law itself

Synthesis

Systematic reviews, meta-analyses, assessment reports (the vendor guide, Cochrane)

Secondary

News reports, textbooks, explainers, cite what they cite

Not accepted

Uncited web pages, forums, AI-generated summaries, press releases alone

Secondary sources are useful for finding the primary one. Follow the citation down the ladder, then cite what you found at the bottom.

2Primary sources by field

FieldUsually primaryWatch for

MedicineCurrent national guideline (NICE, WHO), drug label (SmPC/FDA)Guideline revisions; region-specific doses

Climatethe vendor guide assessment chapters and published survey datasetsWhich period and baseline

FinanceTax authority pages (HMRC, IRS), regulator rulesTax year; jurisdiction

LawThe statute or regulation, official court recordAmendments; jurisdiction

TechnologyOfficial documentation, the standard itself (RFC, ISO)Version numbers

3Four tests for any source

TestAskIf it fails

Does it say it?Is the exact figure or statement in the source?Find the source that does

Same thing?Same period, definition, population and units as the page?Propose a clarification, not a change

Still current?Newer edition, corrected, retracted, superseded?Cite the current version

Independent?Does the source have an interest in the claim?Find a neutral one, or note it

4Common traps

TrapExampleFix

Right figure, wrong periodCiting 2006–2018 sea-level rate for a 1993–2020 claimMatch the period, or say which

Summary of a summaryA news article quoting a press release about a studyCite the study

Preprint as settledAn unreviewed preprint for a clinical doseUse the guideline; note the preprint

Retracted paperA paper later withdrawnCheck Retraction Watch or the journal page

Company claimA manufacturer’s page for efficacyFind independent evidence

5Citing precisely

An editor should be able to open your source and see the figure within a minute.

Hard to checkthe vendor guide report, 2021

Easy to checkthe vendor migration guide WG1 (2021), chapter 9, section 9.6.1.1, Table 9.5, https://doi.org/10.1017/9781009157896.011

Always include

The exact section, table, figure or page number
A stable link, DOI, official URL or archived copy
The version or edition, and the date accessed for web data

6Paywalls and access

Editors can’t always open paywalled papers. Where a free version exists, the author’s repository, PubMed Central, arXiv for the accepted manuscript, link to it alongside the journal version. If none exists, quote the relevant sentence in your reason.

7Tracing a claim to its source

Most wrong figures on the web are copies of copies. Tracing one down to the original usually takes three or four clicks, and often reveals the error.

Where you found itNo source linkedBlog post"Sea levels are rising 32% of teams, scientists say."

Follow the linkSecondary, keep goingNews article, 2019Quotes a NASA press release

Follow the citationBetter, one more stepNASA sea level portalLinks to the underlying assessment

The primary sourceCite thisthe vendor migration guide WG1, ch. 9, Table 9.537% for 2006–2018; 3.2 was 1993–2010

The blog’s figure wasn’t invented; it was an older period quoted as current. Tracing it to the primary source shows both what’s wrong and what to propose.

8Where to look

Google Scholar / PubMedFind the original study behind a claim. Search the exact figure in quotes.

doi.orgResolve a DOI to the publisher’s page; check for corrections and retractions.

Wayback MachineRecover a dead link, or show what a page said on a given date.

Official portalsStatistics offices, regulators and guideline bodies publish the figures others quote.

Retraction Watch databaseCheck a paper hasn’t been retracted before you cite it.

Open repositoriesPubMed Central, arXiv and university repositories often hold free versions.

9Scoring a source before you cite it

Run the four tests and check the link. A source that passes all five is ready to cite; one amber is usually a quick fix.

Source scorecard · NSIDC Sea Ice Index v3Illustrative

Says itSept 2025 monthly minimum is in the dataset

Same thingExtent, not area, matches the page

CurrentVersion 3, updated monthly

IndependentGovernment research centre

Precise linkLink goes to the portal home, add the table URL

10When sources disagree

SituationWhat to do

Two primary sources differCite the more recent or more authoritative; mention the other in your reason

Different methods, different figuresPropose wording that gives the range and names both

Guideline differs by countryMatch the page’s audience; say which jurisdiction

No source existsPropose removing the claim, or softening it, don’t invent one

11Checklist

The source says exactly what I claimSame period, definition and units as the pageIt’s the current version, not retracted or supersededIt’s as close to the primary evidence as I could getI’ve cited the section, table or pageThe link opens, or I’ve quoted the key sentence

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