Open Peer Review Adoption Statistics 2026: How Many Journals Now Publish Reviews

Scholarly publishing is in the middle of a transparency shift. Where peer review was once a closed exchange between authors, editors, and anonymous referees — visible to no one outside the process — a growing share of journals now publish the full text of referee reports, author responses, and editor decisions openly on the web. This is open peer review (OPR), and tracking its spread through the journal system reveals a field changing faster than most researchers realise. As of 2026, more than 730 journals across major publisher portfolios have adopted some form of OPR, up from just 38 journals practising open identities or open reports at the turn of the century. The question researchers increasingly ask is not whether OPR is growing, but how fast, in which disciplines, and what the data say about whether it is working.

This article collates verified open peer review statistics from Clarivate, Leiden Madtrics, the Springer Nature Group, PLOS, Digital Science’s State of Open Data 2025 survey, and primary studies in Scientometrics and Research Evaluation. The goal is to give researchers, students, and journal editors the most accurate snapshot of OPR adoption available in 2026 — covering journal counts, publisher breakdowns, discipline data, researcher attitudes, and what the growth trajectory looks like going forward.

What counts as open peer review

The term “open peer review” covers a family of practices rather than a single policy. The most widely used taxonomy, developed by Ross-Hellauer (2017), identifies seven distinct traits that can each be adopted independently:

When counting “OPR journals” in the literature, most studies focus on the two most verifiable traits: open reports (published referee texts) and open identities (named reviewers). A journal can practise open reports with anonymous reviewers — the most common hybrid — or require full open identities. This distinction matters when interpreting headline journal counts.

The term “transparent peer review” (TPR), used by Clarivate and Springer Nature, refers specifically to the publication of review reports and author responses alongside the article, regardless of whether reviewer names are disclosed. For the purposes of the statistics in this article, OPR and TPR are treated as covering the same core practice unless a source distinguishes them.

How many journals use open peer review in 2026

Counting OPR journals precisely is complicated by definitional variation and incomplete registry coverage. The most rigorous count available in the peer-reviewed literature comes from a 2020 Scientometrics study, which identified 617 journals that had published at least one article with open identities and/or open reports by the end of 2019. A subsequent figure widely cited by Clarivate and Springer Nature put the total at more than 730 journals across major portfolios as of mid-2022, following new policy rollouts by Nature and Wiley.

These counts almost certainly understate the true figure because several large publishers — including MDPI, PLOS, BMJ, EMBO, and Springer Nature itself — publish open peer review content without registering it with Crossref or other DOI providers. When Leiden Madtrics researchers reconstructed the Crossref dataset in 2022, they found that major publishers contributed substantial volumes of OPR content outside the Crossref registry:

Taking the registered and unregistered volumes together, the total number of scholarly articles published with some form of open peer review material almost certainly exceeds 50,000 per year as of 2025–2026, with MDPI alone contributing the majority of that volume through its optional but default OPR option across its entire portfolio of 400+ journals.

Growth trend: from 38 journals in 2001 to 730+

The trajectory of OPR adoption follows the broader pattern of open science: slow early growth, an inflection point around 2017–2018, and accelerating adoption thereafter. The following timeline reconstructs the key milestones from the primary literature:

• 2001: 38 journals practising open identities or open reports — mostly niche titles in biomedicine and atmospheric science
• 2014: MDPI introduces optional OPR at Life, its first journal to carry the policy
• 2016: Nature Communications launches opt-in transparent peer review; 60% of authors opt in within the first year
• 2018: MDPI extends OPR as optional to its entire journal portfolio; peer review records in Crossref still below 10,000
• 2019: 617 journals identified in peer-reviewed literature as having published at least one OPR article (open identities and/or open reports)
• 2020–2021: Crossref peer review records surpass 60,000 per year; Wiley becomes the largest contributor via ScholarOne integration
• 2022: Nature Communications moves to mandatory OPR for all research articles; total identified journals exceeds 730; Nature journal authors previously electing OPR reach approximately 50%
• 2023: eLife launches its full “publish-review-curate” model; 6,200+ submissions in first year; 1,332 Reviewed Preprints published with full open reviews
• 2024: eLife reaches 10,000 cumulative submissions to new model; MDPI opt-in rate for open reviews reported at 21% of all published papers
• June 2025: Nature makes transparent peer review mandatory for all newly submitted primary research papers — the most prominent single-journal policy change to date

The Crossref trajectory alone illustrates the acceleration: from fewer than 10,000 peer review records in 2018 to more than 60,000 in both 2020 and 2021, with reviewer identities disclosed in 39% of those registered records.

Publisher-by-publisher breakdown

Five publishers account for 81% of all identified OPR journals. Here is the detailed picture for each major player as of 2026:

Springer Nature (including BMC and Nature portfolio)

BMC has published reviewer names and pre-publication histories since 1999, making it one of the earliest adopters. Nature Communications launched opt-in TPR in 2016, recording a ~60% opt-in rate in its first year, rising to approximately 70% by November 2022, when it moved to mandatory publication of review exchanges for all research articles. As of early 2024, over one-third of Springer Nature’s journal portfolio — more than 1,000 titles — benefit from integrated early sharing and transparency through the company’s “In Review” platform. In June 2025, Nature itself mandated transparent peer review for all newly submitted primary research articles: review reports and author responses will be published alongside accepted papers, while reviewer identities remain anonymous unless voluntarily disclosed.

PLOS

PLOS (Public Library of Science) has long offered authors the option to publish peer review reports. PLOS ONE, one of the world’s largest journals by article volume (averaging 13,000+ articles per year), offers open review as an option alongside its standard double-blind process. PLOS Medicine publishes referee reports and author responses as standard. In 2021, PLOS contributed more than 7,500 articles with associated open peer review content — not registered with Crossref but publicly visible on the PLOS platform.

Wiley

Wiley became the largest single contributor of TPR records to Crossref during 2020–2021 via its ScholarOne manuscript management system integration. Clarivate’s analysis of TPR at the time identified 123 journals across 7 publishers using ScholarOne-linked TPR, with Wiley accounting for the majority of both journal counts and individual TPR articles. Wiley has since expanded the programme to cover additional titles.

BMJ Group

The BMJ has published signed referee reports, author responses, and editorial decision letters as a “prepublication history” for articles published in its flagship title since the early 2000s. BMJ Open, one of the largest open-access clinical medicine megajournals, carries a transparent review policy as standard. The BMJ’s commitment to open review predates most of the industry’s current interest by more than two decades.

MDPI

MDPI extended optional OPR to all its journals in 2018. The opt-in rate has fluctuated: approximately 23% of papers published open reviews by around 2019–2020, rising to a reported 36.2% for published articles as of mid-2023, before the figure cited for 2024 settled at 21% of all published MDPI papers. With MDPI publishing well over 200,000 articles per year across 400+ journals, even a 21% opt-in rate represents a very large absolute volume of open review content.

Frontiers

Frontiers uses a “collaborative review” system in which the editorial board member coordinating review — the “Associate Editor” — is named on publication. Authors and reviewers can interact directly, though the full review text is not routinely published. This occupies a middle ground between fully closed and fully open review.

Discipline data: where OPR is concentrated

Medical and natural science journals account for 79.9% of all identified OPR journals, according to the 2020 Scientometrics study that remains the most detailed discipline-level analysis available. This concentration reflects several factors:

• Biomedical publishing has the longest history with signed editorials and letters (BMJ since the 1990s)
• Open-science mandates from funders such as Wellcome Trust, NIHR, and the NIH are strongest in life sciences and medicine
• Atmospheric and Earth sciences have strong traditions of open interaction review (e.g., Copernicus Publications’ Atmospheric Chemistry and Physics model, which has operated open interactive review since 2001)
• Physics and mathematics already use arXiv preprints heavily, making pre-review manuscripts de facto public

The social sciences and humanities lag partly because their publishing infrastructure — often involving small society journals or book chapters rather than large journal portfolios — is less amenable to the technology integrations that make TPR at scale feasible. TRANSPOSE, a database of almost 3,000 journal peer review policies compiled by ASAPbio and collaborators, shows that detailed open review policies remain concentrated among STEM titles even as the total number of entries grows.

For researchers writing theses or dissertations in these fields, understanding how peer review norms vary by discipline is directly relevant when evaluating the robustness of literature you cite — a theme covered in our analysis of journal peer review time statistics. When your research is ultimately submitted to a journal, knowing how to write a response to reviewers is equally important: a well-structured reply to referee comments is one of the most consequential documents you will produce as an author.

Understanding how publication bias can distort the literature you review is also important: our guide to publication bias and funnel plot interpretation explains how asymmetric reporting affects the evidence base across disciplines.

Named platforms: eLife, F1000Research, PeerJ, BMJ, PLOS

eLife

eLife launched its radical “publish-review-curate” (PRC) model in January 2023, replacing the traditional accept/reject decision with a system in which every paper that passes an initial editorial screen is published as a “Reviewed Preprint” accompanied by a public eLife assessment and full reviewer reports — regardless of whether the paper is ultimately accepted. By the end of January 2024, eLife had published 1,332 Reviewed Preprints (1,836 including revised versions). The model reached 10,000 total submissions in September 2024. Median time from submission to first published Reviewed Preprint was 91 days in the first year and 98 days in the second — roughly two and a half times faster than eLife’s previous traditional publication route. The model suffered a significant headwind in October 2024 when eLife lost its Web of Science indexing eligibility, causing a drop in submissions from certain geographic regions. Despite this, eLife’s PRC model remains the most prominent example of mandatory fully open peer review at a major life-sciences journal.

F1000Research (now part of Taylor & Francis)

F1000Research pioneered post-publication peer review: articles are published online within 6–14 days of submission, and peer review then takes place in public view. Named reviewer reports and author responses are published alongside the article, and readers can see the progression from initial submission through referee recommendations to the final indexed version. This “publish first, review openly” model directly influenced the design of eLife’s 2023 PRC overhaul.

PeerJ

PeerJ introduced its OPR system at launch in 2013. In its early years, approximately 80% of published authors chose to publish open review reports, and around 40% of reviewers chose to sign their reports — figures that remain among the highest voluntary opt-in rates in the industry. PeerJ’s disciplinary focus on biological and medical sciences means its OPR data skews toward fields already predisposed toward transparency.

BMJ Open

BMJ Open, the BMJ Group’s open-access mega-journal covering all medical research, publishes pre-publication histories including reviewer reports, author responses, and editorial decision letters as a matter of standard policy. It is one of the largest clinical-medicine journals by article volume, making its OPR commitment consequential at scale. The BMJ’s parent journal has operated a similar policy since the late 1990s — making the BMJ Group collectively one of the longest-running OPR practitioners in academic publishing.

PLOS ONE and PLOS journals

PLOS journals offer authors the option to publish peer review reports, and PLOS Medicine makes review reports publicly available as standard. PLOS has also been an advocate for open review at the infrastructure level: the organisation has worked with Crossref and other bodies on standards for peer review metadata, and contributes to ASAPbio’s ReimagineReview catalogue of peer review experiments, which now lists over 60 documented OPR models.

Researcher attitudes: what the surveys show

Support for open peer review among researchers has grown substantially over the past decade, though significant concerns — particularly about open identities — persist.

State of Open Data 2025 (Digital Science / Springer Nature)

The most recent large-scale survey comes from the 2025 edition of the State of Open Data report, published by Digital Science, Figshare, and Springer Nature. Based on more than 4,700 responses across 151 countries, the report found that 75.7% of researchers favour open peer review. This places OPR as the third most supported open-science practice behind open access (88.1% support) and open data (80.9% support) — but clearly in majority territory for the first time in a major longitudinal survey.

Ross-Hellauer et al. 2017 (OpenAIRE survey, n = 3,062)

The foundational attitude survey on OPR was conducted for the OpenAIRE2020 project during September–October 2016 and published in PLOS ONE in 2017. Among 3,062 full responses from authors, editors, and reviewers:

• 60.3% believed OPR as a general concept should become mainstream scholarly practice
• 59% thought publishing reviewer reports would be an improvement over current practice
• 65.4% agreed or strongly agreed that open reports “provide useful information for the reader”
• 60.2% believed that publishing reports would increase review quality
• 50.8% thought signed reviews (open identities) would make peer review worse or much worse

The contrast between attitudes toward open reports (majority positive) and open identities (majority negative) is one of the most consistent findings across OPR attitude research. Reviewers worry that named reviewing exposes them to retaliation, especially when reviewing work by more senior colleagues or controversial authors. This concern is why most OPR policies — including Nature’s 2025 mandatory TPR rollout — publish reviewer reports without automatically disclosing reviewer names.

Machine learning community (2025 survey, n = 1,800+)

A 2025 survey of machine learning researchers (arxiv:2511.23439) found that the ML community broadly supports openness in peer review but expresses specific concerns about resubmission bias — the risk that open reviews from a first rejected submission are visible to editors and reviewers at a second journal, potentially prejudicing the paper’s reception. This discipline-specific concern is increasingly relevant as preprint-to-journal pipelines in CS and ML routinely involve multiple submission rounds.

Does open peer review improve quality and citations

The empirical literature on OPR’s effects on research quality and impact is nuanced. Two patterns appear consistently across studies:

OPR correlates with altmetrics but not with citations

A study published in the Journal of Informetrics (2024), analysing articles from Nature Communications and PLOS ONE, found that papers with open peer review records consistently attracted higher altmetric scores — online attention, downloads, social media engagement — than comparable papers without published reviews. However, the same analysis found no statistically significant difference in citation counts between OPR and closed-review articles at the same journals. This suggests OPR increases the visibility and informal impact of a paper without producing a measurable citation advantage — at least in the short term.

Open identities reduce status bias

Research published in the Journal of Informetrics (2024) on a different dataset found that open identities — where reviewer names are disclosed — appear to reduce the “status bias” observed in anonymous review, where papers from authors at prestigious institutions received more favourable assessments regardless of content quality. When reviewers know their names will be visible, assessments appear to correlate more closely with methodological quality. This finding, though based on limited data, provides one empirical argument for the contested practice of signed reviewing.

Review quality under open models

A scoping review published in Research Evaluation in 2024 (additional experiments required) surveyed recent evidence on key aspects of OPR and found that the effect of open review on review quality — as measured by thoroughness, constructiveness, and accuracy — remains uncertain. Some studies find modest quality gains under open report conditions; others find no effect. The authors note significant methodological heterogeneity across studies and call for controlled experiments before strong conclusions can be drawn.

For researchers using published peer review reports as a quality signal when evaluating sources for a thesis or systematic review, these nuances matter. An openly reviewed article is not automatically higher quality than a closed-review article; the presence of published reports is primarily a transparency indicator rather than a quality certification. Our companion article on predatory journal statistics examines the more extreme end of the quality spectrum — journals that fabricate or bypass peer review entirely.

eLife’s PRC model: early evidence

Analysis of eLife’s first year under its PRC model, published in Scientometrics (2025), found that 77.5% of articles originally rated as “incomplete” showed improved strength-of-evidence descriptions after authors revised their Reviewed Preprints in response to public reviewer feedback. This provides early evidence that the full publish-then-review transparency loop — in which both the original submission and the reviewer critique are public — can drive substantive manuscript improvement. Only 2–3% of authors chose to publish a final version without revising their initial Reviewed Preprint, suggesting that public accountability creates revision incentives even without a formal accept/reject gate.

Researchers tracking retraction rates — another proxy for system integrity — will find complementary data in our coverage of research paper retraction statistics and in the journal acceptance rate data we collect in journal acceptance rate statistics by field.

Writing a thesis or dissertation that engages with the OPR literature? Tesify can help you structure your methodology chapter and literature review around the most current empirical evidence.

Frequently asked questions

Sources and further reading

• Ross-Hellauer, T. et al. (2017). Survey on open peer review: Attitudes and experience amongst editors, authors and reviewers. PLOS ONE.
• Leiden Madtrics. (2022). The growth of open peer review. Leiden University.
• Clarivate. (2022). The current state of open peer review.
• Springer Nature Group. (2025). Transparent peer review now standard for Nature.
• Digital Science / Figshare / Springer Nature. (2025). State of Open Data 2025.
• eLife. (2024). Annual Report: 2024 in review.