No — PLOS ONE is not a predatory journal. It uses genuine, disclosed peer review and is indexed in PubMed/MEDLINE, Scopus, and Web of Science. PLOS ONE pioneered the “megajournal” model, accepting submissions based on methodological soundness rather than perceived novelty, which some researchers mistake for lax review.
What PLOS ONE Is
PLOS ONE is a peer-reviewed, fully open-access journal published by the Public Library of Science (PLOS), a nonprofit publisher. It launched in 2006 with an explicit mission to publish scientifically valid research across all disciplines of science and medicine, evaluated on rigor rather than on subjective judgments of significance. It is funded by article processing charges (APCs) paid on acceptance rather than by reader subscriptions — the same open-access business model used by other large-scale OA publishers such as Scientific Reports, Frontiers, and MDPI. PLOS ONE is listed in the Directory of Open Access Journals (DOAJ) and PLOS is a member of both COPE and OASPA, both of which involve compliance and conduct review.
How PLOS ONE’s Peer Review Process Works
PLOS ONE uses single-anonymized peer review by default: reviewer identities are withheld from authors unless a reviewer chooses to sign their review. After initial in-house screening, a submission is assigned to an Academic Editor — an external, subject-matter-expert researcher, not PLOS staff — who evaluates the manuscript against the journal’s publication criteria and decides whether it needs external peer review. The handling editor recruits independent reviewers, and the editor weighs reviewer feedback alongside their own assessment to reach a decision: reject, major revision, minor revision, or accept. The academic editor, not PLOS as a company, holds final decision-making authority, which is the same basic structural separation used at most reputable peer-reviewed journals. For the general vocabulary this draws on — what “single-anonymized” review means and how it differs from double-anonymized or open review — see CASRAI’s single-anonymized peer review entry and the ANSI/NISO Z39.106-2023 peer review terminology standard that formalized these terms.
PLOS ONE’s Acceptance Criteria: Rigor Instead of Novelty
PLOS ONE publishes a stated list of criteria a submission must meet, and novelty or anticipated impact is deliberately not one of them. In summary, the journal requires that a submission: present original research not published elsewhere; meet high technical standards in its experiments, statistics, and analysis; support its conclusions with the data presented; be written clearly in standard English; comply with relevant ethical and reporting-guideline standards; and make the underlying data available per PLOS’s data policy. A study can be methodologically sound and technically rigorous without being the most novel or highest-impact finding in its field, and PLOS ONE’s editorial policy is to publish it anyway. That is a documented, explicit acceptance standard — not a lowered bar.
Why the Megajournal Model Gets Mistaken for Predatory Practice
Several features of PLOS ONE’s model resemble, on the surface, things researchers are taught to treat as predatory-publisher red flags — without actually being those things:
- High volume. PLOS ONE publishes on the order of tens of thousands of articles a year across every discipline of science and medicine. Predatory operations also publish in bulk, but volume alone doesn’t establish predation; the distinguishing question is whether genuine review happens behind that volume, and at PLOS ONE it does, via the academic-editor-plus-reviewers structure described above.
- Broad, unfocused-looking scope. A journal that publishes physics, ecology, and clinical medicine side by side can look, to someone expecting a narrow subject-specific journal, like it lacks the editorial focus a legitimate journal would have. PLOS ONE’s breadth is a deliberate scope decision, staffed by discipline-specific academic editors for each submission, not an absence of subject-matter vetting.
- Acceptance not gated on novelty. Some researchers equate “will publish work regardless of how groundbreaking it is” with “will publish anything.” PLOS ONE’s actual policy is the opposite of that: it still requires methodological rigor, sound conclusions, and ethical compliance — it just doesn’t use subjective significance as an additional filter on top of those requirements.
- APC-funded, author-pays model. A fee paid by the author on acceptance is also the mechanism predatory journals abuse, collecting a fee without providing genuine review or editorial services. The fee itself doesn’t distinguish the two cases; whether real peer review, indexing, and editorial infrastructure sit behind the fee does. See the open-access business model section below.
For the general warning signs that do distinguish an actually predatory operation — fabricated editorial boards, false indexing claims, no verifiable peer review, deceptive fee disclosure — see CASRAI’s predatory journal entry and guide to identifying predatory journals and publishers. PLOS ONE does not exhibit these markers.
Is PLOS ONE Indexed in Recognized Databases?
Yes. PLOS ONE is indexed in PubMed and included in MEDLINE, and it is also indexed in both Scopus and Web of Science. Consistent, verifiable indexing in these databases is one of the standard checks used to assess a journal’s legitimacy (see CASRAI’s How to Know If an Article Is Peer Reviewed guide for the full method), and predatory operations typically cannot sustain it because indexers themselves evaluate editorial and peer-review quality before granting and maintaining coverage. Individual PLOS ONE articles can of course still vary in quality, as at any large journal, but publisher-wide indexing status is not in question.
PLOS ONE’s Open-Access Business Model
PLOS ONE is funded by an article processing charge paid by authors (or their funders/institutions) upon acceptance, not by readers or subscribers — the standard gold open-access model. PLOS offers fee waivers for authors from low-income countries and has negotiated institutional agreements (“All-In” and similar arrangements) that cover APCs for authors at partner institutions, reducing or eliminating the author-facing charge. This is structurally different from a predatory fee-for-publication scheme in one decisive respect: at PLOS ONE, the fee is charged only after a manuscript has passed the peer-review and editorial-acceptance process described above, and non-payment or fee reduction does not retroactively change what was reviewed. Predatory journals, by contrast, are characterized by collecting a fee with little or no genuine review behind it, often combined with misrepresenting indexing status or editorial board membership. An APC-funded model is not itself a red flag — it is the same business model used across most large legitimate open-access publishers; what matters is whether real editorial and review infrastructure sits behind the fee, and at PLOS ONE it does.
Is PLOS ONE a Predatory Journal?
By the definitions used across the field — see CASRAI’s predatory journal entry — a predatory journal is characterized by the absence of genuine peer review behind a publication-fee business model, typically combined with deceptive practices about editorial board membership, indexing claims, or fees. PLOS ONE does not meet that definition: it discloses its peer review process and acceptance criteria, its academic editors and decision structure are verifiable, it maintains COPE and OASPA-affiliated compliance standards, and it holds consistent, verifiable indexing in PubMed/MEDLINE, Scopus, and Web of Science. The megajournal characteristics that sometimes prompt the question — high volume, broad scope, and acceptance criteria that exclude novelty — are documented, deliberate editorial choices, not evidence of absent review.
How to Verify Peer Review Status for Any Journal
The PLOS ONE-specific facts above answer this one publisher’s case, but the more durable skill is knowing how to check any journal yourself. CASRAI’s How to Know If an Article Is Peer Reviewed guide walks through the concrete checks: journal website disclosure of review policy, indexing in recognized databases, editorial board verifiability, and publisher membership in COPE/OASPA/DOAJ. This site covers the same question for several other frequently-searched publishers and journals: Is MDPI Peer Reviewed?, Is Frontiers Peer Reviewed?, Is Cureus Peer Reviewed?, Is Taylor & Francis Peer Reviewed?, and Is Cambridge University Press Peer Reviewed?
Frequently Asked Questions
Is PLOS ONE a legitimate journal?
Yes. It uses disclosed, single-anonymized peer review with external academic editors, is indexed in PubMed/MEDLINE, Scopus, and Web of Science, is listed in DOAJ, and PLOS is a member of COPE and OASPA. None of the markers used to identify predatory publishers apply to it on the current record.
Why does PLOS ONE accept papers other journals might reject as unoriginal or low-impact?
Because its stated acceptance criteria deliberately exclude novelty and anticipated impact as filters. A submission still has to meet rigorous technical, methodological, and ethical standards; it just isn’t additionally screened for how groundbreaking the finding is. This is the megajournal model PLOS ONE pioneered in 2006, since adopted in some form by other large OA journals.
Is PLOS ONE peer-reviewed the same way as a smaller specialty journal?
The structure is the same — independent external reviewers plus an editor with decision-making authority — but PLOS ONE uses academic editors (external experts) rather than in-house editors, and its acceptance standard is criteria-based rather than significance-based. The review is genuine; the filter applied to the outcome is different.
Does PLOS ONE charge a fee to publish, and does that make it predatory?
Yes, PLOS ONE charges an article processing charge on acceptance, funding its open-access model, with waivers available for authors from low-income countries and coverage through some institutional agreements. A publication fee alone does not indicate a predatory journal; what distinguishes the two is whether genuine peer review and editorial infrastructure sit behind the fee, which is documented and verifiable for PLOS ONE.
Is PLOS ONE indexed in PubMed and Web of Science?
Yes. PLOS ONE is indexed in PubMed and covered in MEDLINE, and is also indexed in Scopus and Web of Science.
Related CASRAI Resources
- How to Know If an Article Is Peer Reviewed
- How to Identify Predatory Journals and Publishers
- Is MDPI Peer Reviewed?
- Is Frontiers Peer Reviewed?
- Is Cureus Peer Reviewed?
- Is Taylor & Francis Peer Reviewed?
- Is Cambridge University Press Peer Reviewed?
- Predatory journal
- Single-anonymized peer review
- ANSI/NISO Z39.106-2023 Peer Review Terminology
