Q: How can I write a second paper based on my thesis without concerns of plagiarism or salami slicing?
I am in the process of converting another chapter of my dissertation into a journal article. This paper has a different focus and a different conclusion but based on the same data I have already described in my first paper. How can I deal with this issue? In other words, how can I write about my data without plagiarizing this section from my previous paper?
You have asked an interesting question and it’s great that you have considered concerns of plagiarism and salami slicing before writing your paper. Unethical practices such as these, when exposed, can be really damaging for a researcher’s career.
As you must already know, it is quite a common practice to convert one’s thesis into one or more journal articles. However, care must be taken that the information presented in the articles does not overlap and each one offers a novel research question. As you have mentioned that your second article from the thesis has a different focus and a different conclusion, it should not ideally be a case of plagiarism.
But since the second study is based on the same dataset, it might raise concerns of salami slicing, an unethical publication practice where more than one paper covers the same population, methods, and research question. To ward off concerns of salami slicing, you must make sure you that the data has been analyzed differently in the two studies and the conclusions are also distinct.
If you feel that the second study is not novel enough for publishing as a new article, you can consider publishing it as a follow-up paper. In your follow-up study, reference your previous article clearly and state that this is a follow up study. Emphasize the need and novelty of the follow up study and state how it adds to the development of knowledge in your field. Make sure you don’t use the same tables and figures as the ones used in the first article.
In any case, please be completely transparent with the journal editor and inform him/her about your thesis as well as the previously published article.