Top 10 Grammar Mistakes and How to Spot them

As much time as we spend at the bench, researchers can spend an equally large chunk of time in front of their computers reading or writing. Many of us love the challenge of penning down experimental results and presenting a story, but, for others, writing a manuscript is one of the hardest parts of being a scientist. This situation is especially true for non-native English speakers who aren’t as familiar with the nuances of the English language as their American or European counterparts. To make life (somewhat) easier, here are a few tricks to identify and rectify common grammar pitfalls to polish that perfect manuscript:

  • Subject-verb disagreement

The subject (person or thing doing the action) and verb (the action being done) must agree in number. Therefore, if the subject is singular, the verb should be singular; if the subject is plural, the verb should be plural. In the examples below, note how the subject count affects verb usage.

Singular: The author analyzes the text. / The result is significant.

Plural: The authors analyze the text. / The results are significant.

  • Faulty parallelism

Parallel sentence structure refers to using the same pattern of words to present a series of ideas. Use of different grammatical forms within the same sentence reduces its clarity and readability. In the examples below, note how the first sentence sounds clunky and confusing. When the faulty parallelism is corrected, the sentence is clearer and more concise.

Incorrect: The cells were washed, plating was performed, and then they proliferated.

Correct: The cells were washed, plated, and allowed to proliferate.

  • Comma fault or comma splice

A comma fault is the improper use of a comma to separate two independent clauses that can serve as two stand-alone sentences. Such an error can be easily corrected by a semi-colon, a comma and conjunction, or a period.

Incorrect: Ten patients exhibited the disease symptoms, two patients died within 48 hours.

       Here, the comma separates two independent clauses. Replacing the comma with a period can easily fix this error.

Correct: Ten patients exhibited the disease symptoms. Two patients died within 48 hours.

  • Incorrect verb tense

Verbs are action words that help the reader place information relative to the past, present, or future time. In scientific writing, verb tenses can be used to reveal information about past events (materials and methods, results, and observations), general truths and facts about current views (literature review and conclusions), and future perspectives (future directions and discussion). Such distinction in verb usage is crucial as different verb tenses can entirely change the scope of a sentence.

Past tense: The temperature increased linearly over time.

Present tense:  The temperature increases linearly over time.

Future tense: Temperature will be measured in the following experiments.

Here, the first sentence refers to a particular experimental observation, while the second sentence is a generalized observation noted by the author across multiple experiments. The third sentence describes the author’s plans for future experiments.

  • Incorrect noun pluralization

Count nouns (entities that you can count, such as animals or samples) and mass nouns (uncountable nouns, such as evidence or water) are quite tricky and cause a lot of confusion in scientific writing. Mass nouns do not have a plural form. Take the word research – it is a mass noun and its verb form is always singular. By contrast, count nouns can have a singular or a plural form. This seemingly simple rule does come with a few exceptions, however. Consider the word data – while it is commonly considered a count noun (singular datum, plural data), it is sometimes treated as a mass noun. In the PLOS ONE article “Clickstream Data Yields High-Resolution Maps of Science,” for example, data is used in its singular form accompanied by the singular form of the verb yields (see subject-verb agreement above).  Such usage is commonly seen in computer science, where data is treated as a mass noun to describe a bulk of information.

  • Ending sentences with prepositions

Many grammarians consider it an abomination to end sentences with prepositions – e.g., with, in, from, for, at, and by.  Surprisingly, it is not grammatically incorrect!

Correct: Which journal was your article published in?

Correct: In which journal was your article published?

While both these sentences are correct, the first one is considered “informal” and is usually avoided in scientific writing. Because a vast majority of readers would consider the first sentence to be incorrect, it would be wise to avoid the possibility of ending a sentence with a preposition and instead rewrite. After all, one of the keys to good writing is keeping readers happy!

  • Apostrophe catastrophe

As a general rule, apostrophes denote possessives (e.g., cell’s nucleus, patient’s DNA) or verb contractions (e.g., don’t, wouldn’t) but never denote plurals. Possession of singular nouns is formed by adding an apostrophe and an s; possession of plural nouns is formed by adding only an apostrophe (e.g., cells’ nuclei, patients’ DNA). Plurals, on the other hand, are formed by only adding an ‘s’ without an apostrophe (e.g., proteins, samples).

  • The dreaded colon and its cousin: the semicolon

Colons and semicolons look and sound similar, but they serve varying purposes in the English language. As baffling as they might be, effective English writing warrants the use of these two relatives. Colons are commonly used to introduce a list or to emphasize a word/phrase.

Three parameters were assessed in the study: viability, migration, and invasion.

      The visiting professor can be summed up in one word: educational.

Semicolons simply denote breaks in a sentence and can join two independent clauses.

The cohort consisted of 82 patients with Alzheimer’s disease; 15 patients were under 55 years of age.         

One rule that should be noted is to never capitalize the first word following either a colon or a semicolon (unless it is a proper noun).

  • Common redundancies and excessive wordiness

Cutting the clutter of words is the easiest way to improve the quality of any piece of scientific writing. However, certain repetitive phrases are so common that they are easily overlooked.

Incorrect: revert back, current trend, actual facts, adequate number of, due to the fact that, it is interesting to note

Such needless repetition of words adds nothing to the meaning of the sentence nor does it make the writing any better. Being concise or avoiding these phrases is the best way to keep the reader glued to your manuscript.

Correct: revert, trend, facts, enough, because, noteworthy

  • Common word mix-ups

Some combination of words in the English language are so similar that they confuse even the best of us. Be mindful, these words are highly context-dependent and not at all interchangeable.

Affect vs. Effect

“Affect” is a verb or the action, while “effect” is a noun and the result of the action.

The drug affected cell viability, and the effect was dramatic.

Accept vs. Except

“Accept” denotes agreement or consent, while “except” implies exclusion.

Everyone accepted the regulations, except the new PI.

An easy way to remember the correct form is Affect implies Action; Accept implies Agreement.

The nitty-gritty of the English language can be wearisome and even infuriating at times. However, to be great scientists, we must be great writers too. Long hours in the lab aside, clear, correct data presentation counts as half the battle toward publishing in a great journal. As English is considered the language of Science, learning to be fluent in English is as essential as learning a new coding language. A wise person once said:

“Yes, English can be weird. It can be understood through tough, thorough thought, though.”


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