Assembling the evidence…
日本の機関リポジトリによるオープンアクセスを推進するため，図書館は研究者に対して論文の提供依頼をおこなってきたが，そのメリットは不明確であり，提供依頼の成功率は低迷している．こうした現状を踏まえ，本研究では被引用数に着目することにより，日本の機関リポジトリによるオープンアクセスのメリットの存否について検証した．日本の機関リポジトリによるオープンアクセス論文の数は限られるものの，その被引用数と様々なタイプのオープンアクセス論文の被引用数の比較からは，日本の機関リポジトリによるオープンアクセスのメリットは確認できなかった．
日本の機関リポジトリによるオープンアクセス論文の数は限られるものの，その被引用数と様々なタイプのオープンアクセス論文の被引用数の比較からは，日本の機関リポジトリによるオープンアクセスのメリットは確認できなかった．
限定的な横断比較で標本規模と信頼区間が示されず，意味のある優位性を除外できない
OAステータスをクローズドからグリーンOA（機関）にすることによる被引用数の変化率は0.99倍
横断的回帰はOAステータス変更による因果的変化を識別しない
ハイブリッドOA，グリーンOA（分野），ブロンズOA，グリーンOA（機関），ゴールドOAの順に係数が高い
報告された点推定値の順序とは一致するが，群間差の検定は示されていない
Derived from the full evaluation — not a separate score.
Strengths
The analysis separates institutional-repository green OA from disciplinary green OA, directly addressing the gap stated in the introduction. This creates a more policy-relevant comparison for Japanese repository managers.
↳ Introduction §1; Methods §2.2
The study analyzes 87,359 Japanese-affiliated 2017 articles using negative-binomial regression and a stated set of bibliometric controls. The model family fits the count nature of citation outcomes.
↳ Methods §§2.2–2.3
The paper links its question to Japanese libraries seeking author deposits and identifies institutional-repository communities as the audience for action. The approximately 50% request-success figure makes the operational problem visible.
↳ Introduction §1; Discussion §4
Limitations
Methods §2.1 claims the coefficients isolate differences caused by OA type, and §§3–4 describe citation changes resulting from switching OA status. The cross-sectional regression supports adjusted associations, not those interventional interpretations.
↳ Methods §2.1; Results §3; Discussion §4
The institutional-green estimate is 0.99 and nonsignificant, but the paper acknowledges that the group is limited without reporting its size or a confidence interval in the supplied text. This prevents assessment of whether a meaningful advantage was excluded.
↳ Abstract; Results §3; Discussion §4
The discussion does not address self-selection into repository deposit, residual confounding, or OA-classification error before recommending urgent repository action. The policy conclusion therefore carries greater certainty than the limitations support.
↳ Methods §2.3; Discussion §4
The paper’s main advance is the separation of institutional and disciplinary green OA in a large Japanese bibliometric sample. Its negative-binomial model and control set support a descriptive adjusted comparison, but Methods §2.1 and §§3–4 interpret the OA coefficients as changes caused by switching status. The 0.99 institutional-green estimate is nonsignificant, yet the acknowledged limited group is not accompanied by its size or confidence interval, so absence of an advantage is not established. The thin limitations discussion and untested repository recommendations keep both quality and translation potential in the preliminary range.
Nabu’s assessment, alongside the field’s view.
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Limited2.9
Confidence mediumThe study adds a specific distinction between institutional and disciplinary green OA in a large Japanese bibliometric sample. The advance is narrow, and the institutional-green null has unreported precision and limited reach beyond the sampled setting.
OACAの序列におけるグリーンOA（機関）の位置付けは明らかになっていない
Negative-binomial regression and several citation-related controls provide a reasonable descriptive model. The analysis nevertheless interprets adjusted associations causally and does not examine deposit selection or OA-classification error.
OAタイプの違いに起因する被引用数の差の正確な把握が可能になる
The paper follows a compact motivation–methods–results–discussion structure and reports the principal estimate directly. Reporting is reduced by switching between the hedged conclusion that an advantage was not confirmed and the stronger statement that no OACA exists.
日本のグリーンOA（機関）のOACAはないといえる
The introduction identifies prior OACA comparisons and the institutional-versus-disciplinary repository gap. The seven-reference framing does not engage selection and confounding concerns, and the discussion moves from a limited null result to urgent action without integrating those uncertainties.
機関リポジトリコミュニティには，早急なアクションが期待される
Caveats3 of 4 checks
The reported model and numerical results are broadly consistent, but the interpretation exceeds what the cross-sectional regression identifies. The institutional-green null is also presented without the group size or confidence interval needed to assess precision.
The study uses bibliometric metadata and does not present a human-subject ethics issue. No suspicious ethics, registration, availability, or conflict claim was identified.
Flags: 0 declared / 5 total
Reference integrity check could not run: no references section detected in extracted text.
0 references in manuscript
No retraction notice found in Retraction Watch.
Sources: Retraction Watch ✓
Where this paper’s evidence sits on the path from initial observation to real-world use.
The paper proposes unified search, disciplinary clustering, and metadata-schema changes. These are suggestions derived from an observational association rather than evaluated interventions.
分野によるクラスタリング機能を実装するといったことが考えられる
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