What Is Salami Slicing in Research?

Salami slicing (or salami publication) means dividing the results of a single study into several smaller papers without a good scientific reason, usually to increase publication counts. It can distort the literature by giving the impression of several independent studies and by making evidence harder to assess.

When splitting is legitimate

• The study has distinct questions, with separate pre-specified objectives and analyses.
• Each paper is complete on its own and addresses a clear, different question.
• The relationship between papers is disclosed and cited.
• Reporting guidelines are followed for each.
• Examples: a primary outcome paper followed by a long-term follow-up; a main trial paper and a pre-specified secondary analysis.

Warning signs of inappropriate splitting

• Same sample, methods and population described in several papers with minor differences.
• Papers that give incomplete information alone.
• Results that belong together being separated to create "extra" papers.
• Non-disclosure of the other papers.

How to decide

1. Ask whether a reader would be better served by one comprehensive paper.
2. Check that each question was defined in the protocol.
3. Make sure each paper includes enough information to be understood independently.
4. Cite and disclose the related papers.
5. Discuss with your mentor and, if needed, the editor.

Illustrative example

Invented for teaching. A cohort study measured 12 outcomes. The authors consider writing 12 short papers. Instead, they publish one paper on the primary outcome and one on pre-specified secondary outcomes, citing each other, with a clear explanation in the cover letter.

Common pitfalls

• Equating more papers with more impact.
• Splitting results after seeing which are significant.

Key takeaways

• Split only for scientific reasons, with disclosure.
• Prioritise completeness and clarity for readers.

This page is general educational information about research methods. It is not medical, legal or regulatory advice; follow your institution's ethics board and your target journal's instructions.