In academic publishing, the least publishable unit (LPU), also smallest publishable unit (SPU), minimum publishable unit (MPU), loot, or publon, is the smallest measurable quantum of publication, the minimum amount of information that can be used to generate a publication in a peer-reviewed venue, such as a journal or a conference. (Maximum publishable unit and optimum publishable unit are also used.) The term is often used as a joking, ironic, or derogatory reference to the strategy of artificially inflating quantity of publications.
Publication of the results of research is an essential part of science. The number of publications is often used to assess the work of a scientist and as a basis for distributing research funds. In order to achieve a high rank in such an assessment, there is a trend to split up research results into smaller parts that are published separately, thus inflating the number of publications. This process has been described as splitting the results into the smallest publishable units.
"Salami publication", sometimes also referred to as "salami slicing", is a variant of the smallest-publishable-unit strategy. In salami publishing, data gathered by one research project is separately reported (wholly or in part) in multiple end publications. Salami publishing, apparently named by analogy with the thin slices made from a larger salami sausage, is generally considered questionable when not explicitly labeled, as it may lead to the same data being counted multiple times as apparently independent results in aggregate studies.
When data gathered in one research project are partially reported as if a single study, a problem of statistical significance can arise. Scientists typically use a 5% threshold (0.95 probability) to determine whether a hypothesis is supported by the results of a research project. If multiple hypotheses are being tested on a single research project, 1 in 20 hypotheses will by chance be supported by the research. Partially reported research projects must use a more stringent threshold when testing for statistical significance but often do not do this.
There is no consensus among academics about whether people should seek to make their publications least publishable units, and it has long been resisted by some journal editors. Particularly for people just getting started in academic publication, writing a few small papers provides a way of getting used to how the system of peer review and professional publication works, and it does indeed help to boost publication count. But publishing too many LPUs is thought not to impress peers when it comes time to seek promotion beyond the assistant professor (or equivalent) level. Also, LPUs may not always be the most efficient way to pass on knowledge, because they break up ideas into small pieces, sometimes forcing people to look up many cross-references. Multiple salami slices also occupy more journal pages than a single synthetic paper that contains the same information. On the other hand, a small piece of information is easily digestible, and the reader may not need more information than what is in the LPU.
- Winning The Games Scientists Play, Carl J. Sindermann.
- Broad, William J (13 March 1981), "The Publishing Game: Getting More for Less", Science, 211: 1137–1139, PMID 7008199, doi:10.1126/science.7008199
- Broad, William; Wade, Nicholas (1983), Betrayers of the Truth: Fraud and Deceit in the Halls of Science, London: Century Publishing, pp. 53–55, ISBN 0-7126-0243-7
- Avoiding plagiarism, self-plagiarism, and other questionable writing practices: A guide to ethical writing
- Duplicate and salami publications. Abraham P, - J Postgrad Med
- "Replication is the only solution to scientific fraud", The Guardian, Chris Chambers and Petroc Sumner.
- "Signs of the times", The Economist, February 24th 2007. This article is based on a presentation by Peter Austin to the American Association for the Advancement of Science.
- "In Defense of the Least Publishable Unit", The Chronicle of Higher Education, Whitney J. Owen.
-  – Video: The hazards of salami slicing