Peer-Reviewed Sources: How to Find and Identify Them

What is peer review?

Peer review is the process by which a manuscript is evaluated by independent experts — peers in the author's discipline — before it can be published. Reviewers assess the paper's originality, methodology, argument, and accuracy, and recommend acceptance, revision, or rejection. An editor makes the final decision based on the reviewers' reports.

A paper that has been peer-reviewed is usually called a scholarly article or refereed article. A journal that runs all of its research articles through peer review is a peer-reviewed journal (also called a refereed journal). Not every item in a peer-reviewed journal is itself peer-reviewed — editorials, book reviews, and letters usually aren't.

Types of peer review

All four types count as "peer-reviewed" for the purposes of academic assignments. Students rarely need to distinguish them — what matters is that the paper has been assessed by experts before or after publication.

Why peer review matters (and its limits)

Peer review filters out obvious errors, demands that claims be supported, and forces authors to address alternative interpretations. It is the closest thing academia has to a quality-control process. Instructors demand peer-reviewed sources because they raise the baseline credibility of a paper's evidence.

Peer review is not, however, a guarantee of truth. It is a filter, not a proof. High-profile retractions — from cold fusion in the 1980s to the COVID-era paper on hydroxychloroquine — show that peer-reviewed papers can still be wrong, and sometimes fraudulent. Cite peer-reviewed sources by default, but keep a critical eye on methodology regardless of where a paper appears.

How to check if a source is peer-reviewed

There is no single authoritative register, but these four methods together will settle almost every case.

1. Check the journal's "About" or "For Authors" page

Every peer-reviewed journal publishes its review policy, usually on the journal's website under About the journal, Editorial policy, or Instructions for authors. Look for phrases like "all submissions undergo peer review", "single-blind review", or "refereed".

2. Look it up in Ulrichsweb

Ulrichsweb (Ulrich's Periodicals Directory) is the standard reference for verifying journal status. A small referee jersey icon next to the journal's entry indicates it is peer-reviewed. Most university libraries provide access to Ulrichsweb through their library portal.

3. Use database filters

Most academic databases allow you to restrict results to peer-reviewed or scholarly sources. In EBSCO and ProQuest, the filter is usually labelled "Peer Reviewed" or "Scholarly (Peer Reviewed) Journals". In Scopus and Web of Science, indexing in the database itself implies peer review.

4. Check the DOAJ for open-access journals

The Directory of Open Access Journals (DOAJ) vets open-access journals for peer-review standards, editorial transparency, and ethical publishing. Listing in DOAJ is a strong signal that an open-access journal is legitimate.

Where to find peer-reviewed articles

These databases either index peer-reviewed content exclusively or let you filter for it directly.

Multidisciplinary

• Scopus — curated index; listing implies peer review
• Web of Science — curated index with citation tracking
• JSTOR — humanities and social-science archive
• Academic Search Complete (EBSCO) — has a peer-reviewed filter
• ProQuest Central — has a peer-reviewed filter

Discipline-specific

• PubMed / MEDLINE — biomedical and life sciences
• PsycINFO — psychology and behavioural sciences
• ERIC — education research
• IEEE Xplore — engineering and computing
• MLA International Bibliography — literature and languages
• Philosophers' Index — philosophy
• Westlaw / HeinOnline — law

Open-access sources

• DOAJ — vetted open-access journals across disciplines
• PubMed Central — open-access biomedical archive
• CORE — aggregator of open-access papers
• OpenAlex — open metadata for scholarly works

Predatory journals: how to spot them

Predatory journals charge author fees to publish papers with little or no real peer review. They often mimic the look of legitimate journals and appear in Google searches. The Think Check Submit initiative and the checklist below cover the most reliable warning signs.

• The journal is not indexed in Scopus, Web of Science, or a discipline-specific database
• Editorial board members have no verifiable institutional affiliation (or deny being on it)
• Review times are promised as "within a week" or "48 hours"
• The journal's name closely mimics a well-known title (e.g. "International Journal of Cell Biology Research" vs. the real Journal of Cell Biology)
• Author fees are high but not disclosed upfront
• The journal solicits submissions via bulk email to unrelated disciplines
• The publisher is on recognised lists of predatory publishers (e.g. Cabells Predatory Reports)

Even one of these signs warrants caution. Two or more, and the journal should not be cited without exceptional justification.

Preprints and conference papers

Preprints are drafts of scholarly papers posted on servers like arXiv, bioRxiv, medRxiv, or SSRN before peer review. They are not peer-reviewed sources — but in fast-moving fields like machine learning and high-energy physics, the preprint is often the primary form of the paper, and the journal version may be years behind.

Conference papers fall between preprints and peer-reviewed articles. Papers at top-tier computer-science conferences (NeurIPS, ACL, CHI) go through reviews that are as strict as — sometimes stricter than — journal peer review. In other fields, conference papers may be only lightly reviewed.

For student assignments that require peer-reviewed sources, use preprints and conference papers only when your field treats them as primary, and make the status explicit if your instructor asks.

Quick summary

"Peer-reviewed" is a tag about process, not about truth. Use peer-reviewed sources as the default — they have passed a real filter — but keep reading with a critical eye, and always double-check unfamiliar journals before you cite them.