Ethics in Action Salami Slicing: What Is it and Is it Ethical?

Salami Slicing: What Is it and Is it Ethical?

By Madeline Schwid, MD

Salami is a cured sausage made of fermented and dried meats that is stuffed into a log-shaped casing and cut up and served as slices. In academic writing, a salami publication refers to cutting a single study into multiple segments that are published separately. This is a pervasive problem in scientific writing. We will examine this issue further through the following case:

You are ready to submit a manuscript for consideration to a journal about a well-received study that you just presented at a national emergency medicine meeting. One of your mentors suggests you take your basic study, break it up, and submit it to three different journals. Is this considered salami publication and is it allowed?

Salami publication is when a single study is broken up into multiple publications or segments. Each piece reports on data from a single study that is split into segments known as a “minimal publishable unit,” meaning that they are just large enough to have reasonable results and conclusions. It is considered a form of self-plagiarism in which the author’s own previously published ideas and content are used without proper attribution. This is in contrast to other forms of plagiarism in which another author’s words are used.

Salami slicing is unethical for a variety of reasons, but one of the most problematic is that it misleads the scientific community and distorts medical evidence that can directly influence patients and clinical practice. For one, duplicate data can be incorporated and double counted into large scale analyses such as a metanalysis, thus influencing the overall data. Splitting data into smaller units can also make it harder to see overall trends in data and so may hinder analysis and conclusions. When these issues translate into clinical practice, patients can be harmed.

Salami slicing gives undeserved credit to authors and wastes journal resources. Academic standing, promotion, and project funding often at least partially rely on academic output and publications. This pressure to publish can be productive in some ways. It encourages people to continue to push the cutting edge of science and develop new ideas but can also encourage quantity of publications at the expense of quality. Through salami slicing, authors can artificially increase the number of publications and can receive more credit for lower value work.

Given that it is very difficult to detect, the frequency of salami publication is unknown. The overall number of journal articles per health science study has increased over time. Among this increase, salami publication is likely common based on studies that have assessed for redundancy in systematic reviews and journals. Unlike more obvious forms of self-plagiarism, there is often no text redundancy in

“Salami slicing is unethical for a variety of reasons, but one of the most problematic is that it misleads the scientific community and distorts medical evidence that can directly influence patients and clinical practice.”

salami publication and so it is difficult for antiplagiarism software to detect. In some cases, it may be identified during editorial review as these articles often have the same sample size, hypothesis, research methodology, results, and authors, although this is also challenging given the articles may be spread through various journals.

Journal policies regarding salami publication are variable, but policies regarding duplicate publication are more common and strict. Duplicate publication is defined as a manuscript that is the same or very similar to a previously published article or data. Unlike salami publication, this has a narrower definition and is more consistent across journals. It is also easier to detect and more universally discouraged.

The definition of salami publication varies between journals and includes vague terms that are subjective and can be open to debate. Because of this, cases of suspected salami publication are often considered on a case-by-case basis, making strict policies difficult to enact. The Committee of Publication Ethics (COPE) has suggested guidelines regarding cases of suspected or confirmed salami publication. Despite this, in addition to the lack of consistent definitions, there is also inconsistency among journals in the consequences for these cases.

The Society for Academic Emergency Medicine has a statement regarding plagiarism that includes duplicate and salami publication in its policy, although salami publication is not explicitly named. Its definition of plagiarism includes “submission of material which ‘overlaps substantially with [material] already published, without clear, visible reference to the previous publication.’” This statement acknowledges the lack of standardized definition of what “substantial overlap” means, but states it is when materials “share the same hypothesis, data, discussion points, or conclusions.” Since substantial overlap includes more than just pure duplication, this statement refers to both duplicate and salami publication. Given the subjectivity of this criterion, cases are determined by two independent reviewers. To avoid salami publication and plagiarism, the previously published manuscripts should be referenced and disclosed. If salami publication is detected, the work will be rejected and depending on the extent of unethical activity, the authors’ institutions may be notified.

Returning to our case, you reply to your mentor that you are concerned that this would be an example of salami publication and suggest you keep the study as one. You explain that you’re worried this could be unethical and highlight the benefit of having a stronger overall manuscript if you keep it as a single manuscript. You are hoping to submit it to a journal with a high impact factor and feel confident that it will be accepted. Your mentor agrees that it is more important to have one good study with a wide audience than many small nonimpactful studies and is glad you brought up your concerns and knowledge about research ethics.

ABOUT THE AUTHOR

Dr. Schwid is a resident physician in the Harvard Affiliated Emergency Medicine Residency program at Massachusetts General Hospital Brigham and Women's Hospital. She served as a 20212022 resident editor on the editorial board of SAEM’s Academic Emergency Medicine journal.