PISS: Editorial Self-Publication in Special Issues

• PISS is a form of editorial misconduct where guest editors publish over 33% of articles in their own special issues, challenging impartial peer review.
• Data from over 112,000 special issues reveals that systematic self-publication occurs frequently and results in significant financial and reputational impacts.
• Policy reforms, including strict endogeny caps and automated cross-matching of authorship, are recommended to safeguard the scientific record.

"Published in Support of Self" (PISS) denotes a form of editorial misconduct in scientific publishing where guest editors of special issues publish a disproportionate number of their own papers within the same issue. The formal threshold for PISS is defined as exceeding 33% endogeny—where “endogeny” is the proportion of non-editorial articles in a special issue authored by at least one of its guest editors. While moderate self-publication is present and often managed responsibly, systematic analyses reveal that PISS persists at a scale comparable to other major forms of scientific fraud, raising substantial concerns regarding the integrity of the scientific record and allocation of publicly funded research resources (Crosetto et al., 12 Jan 2026).

1. Definitions and Quantitative Framework

Endogeny, in this context, refers specifically to the case where a non-editorial article in a special issue lists one or more of the guest editors as authors. The metric of endogeny volume $E$ for a given special issue is defined as: $$E = \frac{N_{\mathrm{endogenous}}}{N_{\mathrm{total}}} \times 100$$ where $N_{\mathrm{endogenous}}$ is the count of eligible (non-editorial) articles with guest-editor authorship and $N_{\mathrm{total}}$ denotes the total number of eligible articles in the issue. A special issue is classified as PISS if and only if $E > 33\%$.

This operationalization excludes editorial or introductory pieces and is designed to detect cases where editorial influence could subvert standard peer review or impartiality expectations.

2. Data Sources and Computational Methods

The systematic analysis of PISS utilizes a dataset comprising all closed special issues published between 2015 and 2025 by five leading publishers: MDPI, Frontiers Media, BioMed Central (BMC), Springer Nature Discover, and Royal Society Phil. Trans. A & B. This corpus spans 112,839 special issues in 904 journals, covering more than 1,005,401 papers.

Data were acquired by a combination of large-scale web scraping (through R packages such as rvest and MDPIexploreR), publisher metadata dumps, and manual curation for sources like BMC. CrossRef metadata were integrated for the disambiguation of author/editor identities. Name-matching procedures involved canonicalization steps (lowercasing, removal of honorifics/hyphens, reducing to “given name + first surname”) to increase matching robustness. False negatives are expected due to residual name ambiguity and conservative matching heuristics.

Validation involved manual spot checks and post-hoc exclusion of multi-year “special issue” pools. Yearly reproducibility and temporal sensitivity (notably a post-2023 decline associated with DOAJ policy warnings) further inform the robustness of these results.

3. Empirical Patterns and Prevalence

Analysis of the combined dataset reveals that endogeny is a widespread phenomenon, but PISS is concentrated. The overall mean endogeny volume in PISS-hosting journals is 14.1%. The distribution by endogeny volume class across special issues is summarized as follows:

Endogeny Volume (E)	Share of Special Issues
0% (“no endogeny”)	38%
0 < E ≤ 33% (“responsible”)	49%
33% < E ≤ 50% (“moderate” PISS)	10%
50% < E ≤ 75% (“severe” PISS)	2%
75% < E ≤ 100% (“extreme” PISS)	1%

Annually, about 1100 special issues (10% of all special issues in PISS-hosting journals) meet the PISS criterion. Endogeny peaked at 16.3% during 2020–2021, with a subsequent decline to 12.5% by 2024—attributed to policy interventions, including the DOAJ's 25%-cap warning.

At the journal level, 15% of journals published zero endogenous papers, while 60% hosted at least one PISS episode. MDPI accounts for 87% of all PISS special issues and 85% of endogenous articles, with the top 30 journals (predominantly MDPI and Frontiers) responsible for 27% of PISS, and the top 100 accounting for 70%.

4. Illustrative Cases and Outlier Analysis

Extreme cases of PISS are rare but persistent. On average, 122 special issues per year exhibit endogeny rates exceeding 75%. Examples of journals with the highest proportion of PISS-classified issues include Frontiers in Built Environment (31%), MDPI Infrastructures (29%), and several MDPI journals such as Minerals, Journal of Marine Science and Engineering, and Water (each ~26%).

Highly endogenous special issues—those where ≥3 of 4 eligible articles are guest-editor-authored—represent a systematic breakdown in editorial impartiality.

5. Impact on Scientific Integrity and the Scholarly Commons

The prevalence of PISS has material consequences for the scientific enterprise. Special issues classified as PISS have collectively published tens of thousands of endogenous articles—a scale comparable to documented episodes of scientific fraud. The estimated financial impact, based on 43,399 endogenous articles at €2,000 APC per article, reaches €87 million over the analyzed 11-year window.

Since scientific publishing constitutes a “common-pool resource,” unchecked PISS practices engender normalization of editorial self-dealing and erode communal trust in the scientific literature.

6. Prevention Strategies and Policy Interventions

The mechanisms required to mitigate PISS are readily implementable. Policy recommendations include:

• Imposition of a strict cap on the endogeny volume per special issue (e.g., $E \leq 33\%$) as a universal standard.
• Automated enforcement using routine guest-editor/author cross-matching within publisher metadata at acceptance.
• Requirement for full, public, and versioned disclosure of special-issue metadata (including editor identities and article types) in open repositories such as CrossRef or OpenAlex.
• Mandates for indexers (DOAJ, Clarivate, Scopus) to routinely monitor endogeny and penalize transgressions via delisting or rating downgrades.
• Prohibition of retroactive removal of “special issue” or “guest editor” tags from article metadata.
• Suspension of special-issue commissions or withdrawal of guest-editor credentials in case of repeated violations.

The objective is to preserve the functional integrity of special issues as a venue for advancing research rather than a mechanism for unchecked guest-editor self-publication.

7. Summary and Recommendations

While a majority of guest editors and special issues conform to responsible endogeny practices (with 87% of special issues maintaining $E \leq 33\%$), a significant fraction of publications is tainted by PISS. Because the technical and administrative apparatus for policing endogeny is already present, regulatory and indexing bodies are advised to codify strict quantitative thresholds, integrate metadata compliance into editorial workflows, and enforce transparent reporting.

These reforms are positioned as essential measures to safeguard scientific credibility and ensure stewardship over the financing and trust that underpin scholarly communication (Crosetto et al., 12 Jan 2026).