Reducing Text Repetition to Lower Your Manuscript’s Similarity Score

Most journals run submitted manuscripts through plagiarism detection software, such as iThenticate, to generate a similarity report that identifies how similar the manuscript’s text is to that of existing publications. If the similarity score is too high, the manuscript will not proceed to peer review. If your manuscript has been flagged for potential plagiarism, refer to our article on Addressing a Report Indicating High Similarity.

Perhaps the simplest way to deal with a high similarity score is to rewrite the flagged sections to reduce repetition and then resubmit the manuscript. The methods section is the part of a manuscript most likely to have a high similarity score, as there are only so many ways to describe common methods, procedures, and materials. If your methods section is flagged as being too similar to existing research, here are ten tips for reducing its repetition and lowering your similarity score.

Tips for Reducing Repetition through Rewriting

1. Use synonyms. Perhaps the clearest way to reduce your similarity score is to replace words in flagged passages with different words that have the same or a similar meaning. However, you must be careful not to replace too many words in the same sentence or use words that are too unusual, or you risk making your text less readable. You should also make sure that the replacement does not change the meaning of the text. Use this technique in moderation and try to replace no more than one or two words in a sentence.

Example (before): The survey was administered between June and July of 2021.

Example (after): The questionnaire was distributed between June and July of 2021.

2. Add (or remove) words. Instead of replacing a word, you can also add (or remove) some. This is easiest to do with adjectives; if you have an adjective that is not absolutely necessary, you can remove it. Removing unnecessary words is also good writing advice in general. Conversely, you can also add an adjective or additional description to break up text flagged for similarity to reduce your score. Make sure that your text is still accurate after any additions or deletions.

Example (before): The warblers became very loud after they spotted a predator.

Example (after): The warblers became loud after they spotted a winged predator.

3. Switch voices. There are two types of grammatical voice in English: active and passive. In the active voice, the subject of the sentence is doing something, and in the passive voice, the subject of the sentence is having something being done to them. To reduce repetition, you can rewrite a sentence from the active to the passive voice, or vice versa.

Example (before): Then, qPCR was performed on the samples.

Example (after): Then, we performed qPCR on the samples.

4. Reorder lists. If your methods section has a list in which the order of items does not matter, you can reduce your similarity score simply by reordering the list. Never reorder a list of consecutive steps; this strategy works best with lists of materials.

Example (before): We mixed 2 g distilled water, 3 g NaCl, and 4 g sucrose together in a flask.

Example (after): We mixed 4 g sucrose, 2 g distilled water, and 3 g NaCl together in a flask.

5. Combine or break up sentences. If you have a long sentence that has been flagged for similarity, you can break it up into smaller sentences, or if you have a short sentence that has been flagged, you can combine it with an adjacent sentence to reduce repetition. In some cases, as in the example below, you can use both strategies at the same time.

Example (before): When we surveyed the literature, we found 12 studies related to type 1 diabetes. We also found 14 related to type 2 diabetes, so taken together we found 26 relevant studies.

Example (after): When we surveyed the literature, we found 12 studies related to type 1 diabetes and 14 related to type 2 diabetes. Taken together, we found 26 relevant studies.

6. Vary sentence structure. This is one of the most powerful ways to quickly reduce similarity, but it can also be tricky if you are not careful. If a sentence has been flagged for repetition, you can rearrange the clauses in the sentence to reduce similarity. When doing this, be sure that the sentence is still easy to understand and has the same meaning.

Example (before): As the satellite fell into a decaying orbit, it began to burn up in the atmosphere.

Example (after): The satellite began to burn up in the atmosphere as it fell into a decaying orbit.

7. Use a variety of transition words. This is a variation of the first tip, but important enough to warrant its own spot. Transition words are used to link sentences together and help the reader follow the logic of your manuscript, and include terms such as moreover, furthermore, however, after, additionally, next, and finally. While not all transition words are interchangeable, correctly using a variety of them in your methods section can not only reduce similarity, but also make your manuscript easier to read.

Example (before): First, we collected the samples. After that, we weighed them. We also measured their diameters. Finally, we disposed of them in accordance with the laboratory’s safety guidelines.

Example (after): To begin, we collected the samples. Then, we weighed them and measured their diameters before we disposed of them in accordance with the laboratory’s safety guidelines.

8. Use specific words instead of pronouns. If you use a pronoun such as he, she, it, or they in a section of flagged text, you can replace it with the specific word that it is referring to. This is also good general writing advice, as it can make your writing clearer. Replacing specific words with pronouns is not recommended to reduce similarity, as this can lead to ambiguity in your writing if you are not careful.

Example (before): After measuring the change in sea level, they moved to the next location and did it again.

Example (after): After measuring the change in sea level, the team moved to the next location and began the process again.

9. Simplify (or expand) phrases. Often, short phrases can be reduced to a single word. While it is generally good writing advice to write as simply and concisely as possible, if necessary, you can also expand one simple word into a short phrase instead. Both strategies can help you reduce your similarity score.

Example (before): After we welded the beams, we measured their combined length.

Example (after): After welding the beams, we measured the length of both of them combined.

10. Combine multiple strategies. While all these strategies on their own can reduce repetition, and thus your similarity score, the most effective way to easily accomplish this is to combine multiple strategies, even in the same sentence.

Example (before): We monitored social media posts there for two months—April and May—and found that most commenters fell into one of two categories: supporters or opponents of the law.

Example (after): After monitoring posts on WeChat in April and May, we discovered that most users either strongly supported or opposed the law.

If you are worried that your manuscript might be similar to existing research—whether because it uses common methods or you have already published papers on the same topic—you can also take advantage of LetPub’s Plagiarism Check service, which will let you see your manuscript’s similarity report on iThenticate before you submit it to a journal. Then, using the above tips, you can rewrite any manuscript section to reduce your similarity score and ensure your manuscript enters the peer review process.