Duplicate publications in the otolaryngology literature

Assessment of Duplicate Publication of Chinese-Sponsored Randomized Clinical Trials

IMPORTANCE

Duplicate publications of randomized clinical trials are prevalent in the health-related literature. To date, few studies have assessed the interaction between duplicate publication and the language of the original publication.

OBJECTIVE

To assess the existence of duplicate publication and the extent to which duplicate publication is associated with the language of the original publication.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective cohort study, eligible randomized clinical trials were retrieved from trial registries, and bibliographic databases were searched to determine their publication status. Eligible randomized clinical trials were for drug interventions from January 1, 2008, to December 31, 2014. The search and analysis were conducted from March 1 to August 31, 2019. The trial registries were either primary registries recognized by the World Health Organization or the Drug Clinical Trial Registry Platform sponsored by the China Food and Drug Administration.

EXPOSURES

Individual randomized clinical trials with positive vs negative results.

MAIN OUTCOMES AND MEASURES

Journal articles were classified as main articles (determined by largest sample size and longest follow-up among all journal articles derived from that randomized clinical trial) and duplicates. The duplicates were classified into 4 types: (1) unreferenced subgroup analysis (article did not disclose itself as a subgroup analysis or reference its main article); (2) unreferenced republication (article did not disclose itself as a replicate of the main article or reference it); (3) unreferenced interim analysis (article did not disclose itself as an interim analysis or reference its main article); and (4) partial duplicate (article did not disclose its sharing a subset of participants with other articles or reference them).

RESULTS

Among 470 randomized clinical trials published by August 2019 as journal articles, 55 (11.7%) had 75 duplicates, of which 53 (70.7%) were cross-language duplicates. Of the 75 duplicates, 33 (44.0%) were unreferenced republications, 25 (33.3%) unreferenced subgroup analyses, 15 (20.0%) unreferenced interim analyses, and 2 (2.7%) partial duplicates. When the main article of a randomized clinical trial was published in Chinese, those with positive findings were 2.48 (95% CI, 1.08-5.71) times more likely to have subsequent duplicate publication than those with negative findings.

CONCLUSIONS AND RELEVANCE

In this study, most duplicates were cross-language duplicates and the most common type was unreferenced republication of the main article. Duplicate publication bias exists when the main articles of randomized clinical trials were published in Chinese, potentially misleading readers and compromising journals and evidence synthesis.

Duplicate and salami publication: a prevalence study of journal policies

BACKGROUND

Duplicate and salami publication are unethical, but are common practices with substantial consequences for science and society at large. Scientific journals are the 'gatekeepers' of the publication process. We investigated journal policies on duplicate and salami publication.

METHODS

In 2018, we performed a content analysis of policies of journals in the disciplines of 'epidemiology and public health' and 'general and internal medicine'. Journal policies were searched, extracted, coded and cross-checked. The associations of disciplinary categories and journal impact factors with journal policies were examined using Poisson regression models with a robust error variance.

RESULTS

A total of 209 journals, including 122 in epidemiology and public health and 87 in general and internal medicine, were sampled and their policies investigated. Overall, 18% of journals did not have any policies on either practice, 33% only referred to a generic guideline or checklist without explicit mention about either practice, 36% included policies on duplicate publication and only 13% included policies on both duplicate and salami publication. Having explicit journal policies did not differ by journal disciplinary categories (epidemiology and public health vs general and internal medicine) or impact factors. Further analysis of journals with explicit policies found that although duplicate publication is universally discouraged, policies on salami publication are inconsistent and lack specific definitions of inappropriate divisions of papers.

CONCLUSIONS

Gaps exist in journal policies on duplicate and salami publication, characterized by an overall lack of explicit policies, inconsistency and confusion in definitions of bad practices, and lack of clearly defined consequences for non-compliance. Scientific publication and the academic reward systems must evolve to credit good research practice.

Duplicate Publication in the Journal of Hand Surgery

This study evaluates the extent of duplicate publication in the Hand Surgery literature. A retrospective review of original articles published in the American and the British & European editions of Journal of Hand Surgery during the years 1999 and 2000 was performed using MEDLINE (PUBMED) search engine. Index articles suspected of dual publication were identified by using key words in the title and the names of the first, second and last authors. The full initial text was carefully studied and suspected duplicate articles were classified as dual, potentially dual or fragmented. Six hundred articles were evaluated, of which 25 (4%) index articles were identified with 33 “suspects”. Eleven “index” and 15 “suspected” articles were cleared on closer scrutiny. Thus 14 “index” articles (2%) were found to be associated with 18 duplicated articles. Of these, four were classified as dual, five as potentially dual and nine as fragmented. We conclude that although duplicate publication of articles in the Journals of Hand Surgery (American and British/European Volumes) does occur, the incidence in the sample studied is lower than some other surgical journals.

Duplicate Publication and Related Problems in the Pediatrics Literature

Objective. The aim of this study was to (a) determine the rate of redundant publication in the pediatrics literature and (b) to characterize these articles. Methods. Index articles in JAMA Pediatrics, Pediatrics, and the Journal of Pediatrics from 2010 were identified using PubMed. Possible redundant material from 2008 to 2012 were searched using the authors' names. Suspected duplicates were categorized into "duplicate publication" or "salami-slicing" (part of the index article repeated or continued). Results. Of the 1838 index articles, 39 (2.1%) were found to have some form of redundancy. Specifically, 45 articles were identified as salami-sliced, which corresponded to the 39 index articles. Fifteen salami-sliced articles did not reference the corresponding index article, 2 vaguely referenced the index article, and 28 had clear references to the respective index article. Conclusion. Salami-slicing was a common practice. Salami-slicing may be acceptable in certain cases but authors should clearly reference the index article.

Duplicate publication of articles used in meta-analysis in Korea

With the increasing use of meta-analysis, duplicate publication of original research is particularly problematic. Duplicate publication can result in an inappropriate weighting of the study results. The purpose of our study was to assess the incidence and characteristics of duplicate publications in Korea, and to estimate the impact of duplicate publication on meta-analyses. The meta-analysis literature written by Korean authors was searched using the online search engines PubMed, KMbase, and KoreaMed. Duplication patterns were classified into the following 4 combinations: identical samples and identical outcomes (copy), identical samples and different outcomes (fragmentation), increased samples and identical outcomes (imalas), and decreased samples and identical outcomes (disaggregation). To estimate the multiple publication bias, we performed a meta-analysis with and without duplicated data. We estimated that 6 (6.9%) of the 86 analyzed meta-analyses included duplicate publications, and 6 of the 1,194 articles (0.5%) used in the meta-analyses were duplicate publications. In this study, duplicate publications were usually due to disaggregation and overlapping (imalas) publications. Of 6 duplicated articles, 1 was considered a copy (16.6%); 1, a fragmentation (16.6%); 2, imalas (33.3%); and 2, disaggregations (33.3%). There was an increase in the mean effect size and fail-safe number with duplicated data. Our study found only 6 instances of duplicate publication after analyzing 1,194 articles used in meta-analyses written by Korean authors. However, 6.9% of the meta-analyses included duplicate publications. Our findings suggest that meta-analyses should be interpreted cautiously, taking into account the possibility of duplicated studies.

Duplicate publication rate decline in Korean medical journals

The purpose of this study was to examine trends in duplicate publication in Korean medical articles indexed in the KoreaMed database from 2004 to 2009, before and after a campaign against scientific misconduct launched by the Korean Association of Medical Journal Editors in 2006. The study covered period from 2007 to 2012; and 5% of the articles indexed in KoreaMed were retrieved by random sampling. Three authors reviewed full texts of the retrieved articles. The pattern of duplicate publication, such as copy, salami slicing (fragmentation), and aggregation (imalas), was also determined. Before the launching ethics campaign, the national duplication rate in medical journals was relatively high: 5.9% in 2004, 6.0% in 2005, and 7.2% in 2006. However, duplication rate steadily declined to 4.5% in 2007, 2.8% in 2008, and 1.2 % in 2009. Of all duplicated articles, 53.4% were classified as copies, 27.8% as salami slicing, and 18.8% as aggregation (imalas). The decline in duplicate publication rate took place as a result of nationwide campaigns and monitoring by KoreaMed and KoreaMed Synapse, starting from 2006.

Current incidence of duplicate publication in otolaryngology

OBJECTIVES/HYPOTHESIS

Duplicate publication--deemed highly unethical--is the reproduction of substantial content in another article by the same authors. In 1999, Rosenthal et al. identified an 8.5% incidence of duplicate articles in two otolaryngology journals. We explored the current incidence in three otolaryngology journals in North America and Europe.

STUDY DESIGN

Retrospective literature review.

METHODS

Index articles in 2008 in Archives of Otolaryngology-Head and Neck Surgery, Laryngoscope, and Clinical Otolaryngology were searched using MEDLINE. Potential duplicate publications in 2006 through 2010 were identified using the first, second, and last authors' names. Three authors independently investigated suspected duplicate publications--classifying them by degree of duplication.

RESULTS

Of 358 index articles screened, 75 (20.9%) had 119 potential duplicates from 2006 to 2010. Full review of these 119 potential duplicates revealed a total of 40 articles with some form of redundancy (33.6% of the potential duplicates) involving 27 index articles (7.5% of 358 index articles); one (0.8%) "dual" publication (identical or nearly identical data and conclusions to the index article); three (2.5%) "suspected" dual publications (less than 50% new data and same conclusions); and 36 (30.3%) publications with "salami-slicing" (portion of the index article data repeated) were obtained. Further analysis compared the likelihood of duplicate publication by study source and subspecialty within otolaryngology.

CONCLUSIONS

The incidence of duplicate publication has not significantly changed over 10 years. "Salami-slicing" was a concerning practice, with no cross-referencing in 61% of these cases. Detecting and eliminating redundant publications is a laborious task, but it is essential in upholding the journal quality and research integrity.

Prevalence of covert duplicate publications in Budd-Chiari syndrome articles in China: a systematic analysis

BACKGROUND

Covert duplicate publication is unquestionably unethical and problematic. Approximately 3000 articles describing Budd-Chiari syndrome in China have been published. However, no study has yet explored the prevalence of covert duplicate publications among these articles.

METHODS

We retrieved original articles regarding Budd-Chiari syndrome in China via the PubMed, Chinese Scientific and Technological Journal (VIP), and China National Knowledge Infrastructure databases. The prevalence of covert duplicate publications was evaluated across publication dates, institutional grades, and academic levels of the journals.

RESULTS

Overall, 1914 articles were included in our analysis. These articles were produced by 632 institutions and published in 463 journals. Overall, 10% (184/1914) of the articles, 10% (62/632) of the institutions, and 26% (119/463) of the journals were involved in covert duplicate publications. A decreasing trend in the prevalence of covert duplicate publications over time was observed. The prevalence of covert duplicate publications was significantly higher in tertiary hospitals than in primary hospitals or unclassified institutions (10.0% vs 3.8%, P = .038), but the prevalence was similar between tertiary and secondary hospitals (10.0% vs 9.3%, P = .72). The prevalence of covert duplicate publications was significantly higher in Science Citation Index journals than in Chinese Academic Core journals (23.9% vs 10.3%, P = .001) and other journals (23.9% vs 8.3%, P < .001).

CONCLUSIONS

Covert duplicate publications are relatively common among articles on Budd-Chiari syndrome in China. The high prevalence of covert duplicate publication in Science Citation Index journals should remind English-language journal editors to verify whether the articles submitted by Chinese researchers have been published in Chinese-language journals.

Duplicate publications: A sample of redundancy in the Journal of Urology

PURPOSE

: Redundant publications occur when authors publish a partial or complete duplicate of data from an existing manuscript. The push for academic advancement in medicine may result in redundant publications that erode the quality of literature. We sampled the extent of redundancy within the Journal of Urology.

METHODS

: Original articles published in the Journal of Urology in 2006 were reviewed. MEDLINE was used to identify suspected duplicate publications by combining the last names of the first, second and last authors with keywords provided by the article. Results were limited to 2004 to 2008. Two investigators reviewed the suspected duplicate publications and classified them as duplicate, probable duplicate and salami-slicing.

RESULTS

: We screened 723 original articles. Of these original articles, 13 (1.8%) had some form of redundancy. One (0.1%) original article had a duplicate article, 5 (0.7%) original articles had probable duplicates, and 7 (1%) original articles were salami-sliced. The proportion of redundant articles published prior to, and following, their 2006 index article was 5/13 (38.5%) and 7/13 (53.8%), respectively. One duplicate (7.7%) was published in the same month as its index.

CONCLUSION

: Detection of redundant publications is a laborious process for reviewers and editors. This sampling of the Journal of Urology revealed that the duplication rate in this journal is small, but significant. Further assessment of the urological literature is warranted.

Identifying duplicate content using statistically improbable phrases

MOTIVATION

Document similarity metrics such as PubMed's 'Find related articles' feature, which have been primarily used to identify studies with similar topics, can now also be used to detect duplicated or potentially plagiarized papers within literature reference databases. However, the CPU-intensive nature of document comparison has limited MEDLINE text similarity studies to the comparison of abstracts, which constitute only a small fraction of a publication's total text. Extending searches to include text archived by online search engines would drastically increase comparison ability. For large-scale studies, submitting short phrases encased in direct quotes to search engines for exact matches would be optimal for both individual queries and programmatic interfaces. We have derived a method of analyzing statistically improbable phrases (SIPs) for assistance in identifying duplicate content.

RESULTS

When applied to MEDLINE citations, this method substantially improves upon previous algorithms in the detection of duplication citations, yielding a precision and recall of 78.9% (versus 50.3% for eTBLAST) and 99.6% (versus 99.8% for eTBLAST), respectively.

AVAILABILITY

Similar citations identified by this work are freely accessible in the Déjà vu database, under the SIP discovery method category at http://dejavu.vbi.vt.edu/dejavu/.

Deja vu: a database of highly similar citations in the scientific literature

In the scientific research community, plagiarism and covert multiple publications of the same data are considered unacceptable because they undermine the public confidence in the scientific integrity. Yet, little has been done to help authors and editors to identify highly similar citations, which sometimes may represent cases of unethical duplication. For this reason, we have made available Déjà vu, a publicly available database of highly similar Medline citations identified by the text similarity search engine eTBLAST. Following manual verification, highly similar citation pairs are classified into various categories ranging from duplicates with different authors to sanctioned duplicates. Déjà vu records also contain user-provided commentary and supporting information to substantiate each document's categorization. Déjà vu and eTBLAST are available to authors, editors, reviewers, ethicists and sociologists to study, intercept, annotate and deter questionable publication practices. These tools are part of a sustained effort to enhance the quality of Medline as ‘the’ biomedical corpus. The Déjà vu database is freely accessible at http://spore.swmed.edu/dejavu. The tool eTBLAST is also freely available at http://etblast.org.

Redundant publication in the journal Radiology

PURPOSE

To retrospectively quantify the incidence of redundant publication in the journal Radiology and to compare the present study findings with those published for other journals and medical specialties.

MATERIALS AND METHODS

Two readers estimated the incidence of the redundant publication of original articles in Radiology in the year 2001. Original research articles published in 2001 were analyzed by searching MEDLINE on the PubMed server to identify articles that may have represented a duplication of the original Radiology article. MEDLINE was searched between January 1999 and December 2003 by using the surname and initial(s) of the first author. Potentially redundant articles were identified after similarities in titles and abstracts were analyzed. The full versions of all potentially redundant articles and of the corresponding index articles were then retrieved from the library. The potentially redundant article was then compared with the index article. Criteria for redundant publication were as follows: Compared with the index article, the potentially duplicate article had (a) a similar hypothesis, (b) a similar number of subjects, (c) similar results, (d) at least one author in common, and (e) no or little new information.

RESULTS

In 2001, 362 original research articles were published in Radiology. Two instances of redundant publication were found among these articles, and both were considered to be partially redundant publications due to series expansions (ie, increased numbers of study subjects) of 50% and 52%.

CONCLUSION

Redundant publication appears to be less frequent in Radiology than in the other journals and specialties for which redundant publication information has been reported.

Duplicate Publications in Korean medical journals indexed in KoreaMed

Duplicate publication is considered unethical. It has several negative impacts. To estimate the frequency and characteristics of duplicate publications in Korean medical journals, we reviewed some portion of Korean journal articles. Among 9,030 articles that are original articles indexed in KoreaMed from January to December 2004, 455 articles (5%) were chosen by random sampling. PubMed, Google scholar, KMbase, and KoreaMed were searched by two librarians. Three authors reviewed titles, abstracts, and full text of index articles and suspected articles independently. Point of disagreement were reconciled by discussion. Criteria for a duplicate publication defined by editors of cardiothoracic journals and International Committee of Medical Journal Editors were used. A total of 455 articles were evaluated, of which 27 (5.93%) index articles were identified with 29 duplicate articles. Among 27 index articles, 1 was quadruple publication and 26 were double publications. Of 29 duplicated articles, 19 were classified as copy, 4 as fragmentation, and 6 as disaggregation. The proportion of duplicate publications in Korean medical journals appears to be higher than expected. Education on publication ethics to researchers is needed.

Déjà vu--a study of duplicate citations in Medline

MOTIVATION

Duplicate publication impacts the quality of the scientific corpus, has been difficult to detect, and studies this far have been limited in scope and size. Using text similarity searches, we were able to identify signatures of duplicate citations among a body of abstracts.

RESULTS

A sample of 62,213 Medline citations was examined and a database of manually verified duplicate citations was created to study author publication behavior. We found that 0.04% of the citations with no shared authors were highly similar and are thus potential cases of plagiarism. 1.35% with shared authors were sufficiently similar to be considered a duplicate. Extrapolating, this would correspond to 3500 and 117,500 duplicate citations in total, respectively.

AVAILABILITY

eTBLAST, an automated citation matching tool, and Déjà vu, the duplicate citation database, are freely available at http://invention.swmed.edu/ and http://spore.swmed.edu/dejavu

Duplicate publications: redundancy in plastic surgery literature

The practice of duplicate publication has been condemned widely in the scientific community and several studies have been conducted to establish the level of the problem in various surgical fields. A retrospective review of original articles from the British Journal of Plastic Surgery and Plastic and Reconstructive Surgery during 2000 was conducted, using Medline (PubMed). A total of 431 abstracts were screened, from which 27 index articles related to 33 'suspected redundant' publications. Further evaluation was carried out by comparing the full text versions of these articles and assigning a grade of non-dual, dual, potentially dual and 'salami-slicing'. Only four suspect articles were confirmed as having some degree of redundancy, and these related to three index articles (3/431, <1%). The incidence of duplication in plastic surgery literature seems to be much lower compared to other surgical specialties, providing reassurance for reviewers, editors and readers of these journals.

Bias from industry trial funding? A framework, a suggested approach, and a negative result

Bias from funding sources of trials would threaten their validity. Meta-analyses of high quality acute pain and migraine trials were used to explore the hypothesis that industry funding of clinical trials produced more favourable results than non-profit sponsorship. Analyses were planned to evaluate whether industry-sponsored trials had different results from trials funded by academic or other non-profit sources, but of 176 trials, only two were supported by non-profit sources, while 31 provided no statement of support. An alternative method is proposed within industry-sponsored trials, looking at conflicting industry interests for the same drug, used either as test or comparator treatment. Fifty-three trials used an analgesic as test and 90 as comparator, allowing comparisons to be made for aspirin 600/650 mg, ibuprofen 400 mg, paracetamol (acetaminophen) 1000 mg, rofecoxib 50 mg and sumatriptan 50 and 100 mg. Only for sumatriptan 50 and 100 mg, with the outcome of headache response at 2 h, was there any significant difference between the drug used as a test or as a comparator. The direction was for higher (worse) NNTs with sumatriptan as comparator. Investigating potential industry bias through the funding source of trials is unlikely to be adequate because of a dearth of trials funded by non-profit organisations. We propose a method based on potential conflict of interest within industry-sponsored trials. Using this method, established clinical trial results in acute pain and migraine appear to be unbiased.