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The pitfalls of “salami slicing”: Focus on quality and not quantity of publications

The pitfalls of “salami slicing” SALAMI SLICING Imagine you have just completed a controlled study about a new intervention in a birthing center. You have two sets of results: one set on mothers and one on infants. Should you write two papers—each reporting a different set of results—and send these papers to two different journals? Or consider a case where you are studying several closely related compounds.1 Should you write a separate paper for each compound? The answer to both questions is no. Editors consider these as cases of “salami slicing”— unethically fragmenting the results of a single study and reporting them in multiple papers.

Study about a new intervention in a birthing centre



Journal 1

Journal 2

The pitfalls of “salami slicing” What is salami slicing? It refers to the practice of partitioning a large study that could have been reported in a single research article into smaller published articles.2 In other words, it means breaking up a single research paper into their “least publishable units,” with each paper reporting different findings from the same study. A set of papers are referred to as salami publications when more than one paper covers the same population, methods, and research question.3

SALAMI SLICING Study about a new intervention in a birthing centre Mothers


Journal 1

Journal 2

The pitfalls of “salami slicing” Journal Speak When a manuscript is submitted to the American Journal of Speech-Language Pathology, one of the many decisions that must be made is whether it meets or exceeds a ‘least publishable unit’ criterion. To make this decision, I ask myself the following question: “Does this manuscript contain enough new data, knowledge, or insight to warrant publication?”4

- Editor, American Journal of Speech-Language Pathology

The pitfalls of “salami slicing� A journal editor gave the following examples to illustrate a case of salami slicing.4

Scenario 1: A scientist begins a new line of research. The scientist has developed a new instrument for collecting data, one that is more precise than the current instruments. The main study may take a year or over to complete. The scientist submits a manuscript for publication describing the new instrument before completing the main study.

Description of new instrument

Can you determine which is the case of salami slicing?



The pitfalls of “salami slicing” APHASIA GROUPS


Control group

Control group Manuscript 2


Manuscript 1

Control group



Scenario 2: After determining the research question and setting the study design, a scientist collects data on three groups of participants. Two of the groups have different types of aphasia (Groups A and B), and one group is a control group. The scientist submits two manuscripts for publication: one comparing Group A with the control group, and the other comparing Group B with the control group.


The pitfalls of “salami slicing� Answer: Scenario 1 is not likely to be considered as a salami publication. The new instrument was not a part of the research question, but rather was NOT A SALAMI PUBLICATION developed to answer the research question. When publishing the main study, the scientist need not describe the instrument in detail in the Methods section, but rather should refer to the previous publication. Scenario 2 is likely to be considered a salami publication. All of the data should be published in a single manuscript.


The pitfalls of “salami slicing” What’s wrong with doing this?


Career distortions: Researchers practise salami slicing to increase their volume of publications, born of the “publish and perish” culture.5 In the short term, salami science may allow researchers to progress faster in their careers or receive more funding than they actually merit, owing to the greater number of publications in their resume.6,7 However, this can be harmful in the long term, since it diminishes the value of each publication. You may have managed to add a long list of publications to your name through salami publications, but if a committee were to review the body of work, they might conclude that the studies themselves are not substantial enough.

The pitfalls of “salami slicing�


Harm to science. Publishing unnecessary and repetitive information increases the amount of literature, but not the amount of knowledge. If closely related data from a single group is divided across several papers, readers who access only one of the papers may misinterpret the findings. Further, multiple reports may cause a set of findings to be given more importance that it deserves. For instance, in the example mentioned in the beginning, another researcher conducting a metaanalysis on the new intervention for birthing centers might erroneously assume that this intervention has been studied twice, rather than once.


What’s wrong with doing this?

The pitfalls of “salami slicing” Journal Speak As earlier editorials have pointed out, multiple reports of the same observations can overemphasize the importance of the findings, overburden busy reviewers, fill the medical literature with inconsequential material, and distort the academic reward system.6

- Editorial, New England Journal of Medicine

The pitfalls of “salami slicing� Is it always wrong to report a single study through multiple papers? If the original dataset is extremely large (e.g., a population-based study) or when the dataset takes years to collect and analyze, the authors have justifiable and legitimate grounds to report the research in more than one paper.6,8 However, each paper should address distinct and important questions.8 If the study is motivated and designed around a single hypothesis, its results should be presented to the readers as a single package, regardless of the size of the dataset.4

The pitfalls of “salami slicing� If you do have legitimate grounds to submit multiple publications based on the same study, ensure that you inform the editorial office about any possibly overlapping information (including whether any of the control data in a manuscript are also included among the control data in another manuscript or whether you have previously published articles on the same or a closely related topic) either before submitting a paper or in the accompanying cover letter.9 In addition, refer to all related studies within the manuscript.

The pitfalls of “salami slicing� Journal Speak When authors fail to disclose all relevant work, they deny referees and editors the opportunity of assessing the true extent of its contribution to the broader body of research.10 -Editorial, Nature Materials A reasonable yardstick by which to judge redundancy is to ask whether a single paper would be more cohesive and informative than two, without being excessively long.7 - Annals of the Rheumatic Diseases

The pitfalls of “salami slicing� Conclusion A paper will have a greater chance of publication as a full-scale study, rather than a fragment of a larger study. Focus on the quality of your publications, not quantity. Salami slicing to increase the number of publications on your resume might only end up sabotaging your research career at a later stage.

The pitfalls of “salami slicing” REFERENCES: 1. 2. 3. 4. 5. 11. 12. 13. 14. 15.

McCann G (n.d.). Common Reasons for Rejection. Journal of Materials Chemistry, Author Guidelines. Cicutto L (2008). Plagiarism: Avoiding the peril in scientific writing. Chest. 133(2): 579-81. doi: 10.1378/chest.07-2326 Committee on Publication Ethics (COPE) (2005). Cases: Salami publication. Accessed on July 7, 2011. Available at Hoit J (2007). Salami science. American Journal of Speech-Language Pathology, 16: 94. doi: 10.1044/1058-0360(2007/013). Abraham P (2000). Duplicate and salami publications. Journal of Postgraduate Medicine, 46: 67 Kassirer J & Angell M (1995). Redundant publication: A reminder (Editorial). The New England Journal of Medicine, 333: 449-50. Doherty M (1996). The misconduct of redundant publication. Annals of the Rheumatic Diseases, 55(11): 783-85. Tobin M (2002). AJRCCM’s policy on duplicate publication: Infrequently asked questions. American Journal of Respiratory and Critical Care Medicine, 166: 433-34. Bankier A, Levine D, Sheiman R, Lev M, Kressel H (2008). Redundant publications in radiology: Shades of gray in a seemingly black-and-white issue. Radiology, 247: 605-7. doi: 10.1148/radiol.2473080298. Editorial (2005). The cost of salami slicing. Nature Materials 4(1). doi: 10.1038/nmat1305.

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The pitfalls of salami slicing focus on quality and not quantity of publications