Academic writing is more than just conveying ideas—it’s about doing so with clarity, precision, and credibility. Even the most brilliant insights can lose their impact if grammatical errors cloud them. Small grammar mistakes can undermine your professionalism and distract readers from your message, whether you’re writing a research paper, thesis, or journal article.
But here’s the good news: most errors are common, recognizable, and—once you’re aware of them—completely avoidable.
In this blog, we’ll walk through 20 of the most common grammatical mistakes in academic writing. For each one, you’ll see a real-world example of what not to do, followed by a corrected version and a quick explanation. Whether you’re a student, researcher, or someone who wants to write more clearly, these examples will help you polish your prose and strengthen your academic voice.
Let’s dive in—and take your writing from “good enough” to truly scholarly.
1. Subject-verb agreement
One of the most fundamental rules in grammar is that the subject and verb in a sentence must agree in number—singular subjects take singular verbs, and plural subjects take plural verbs. It sounds simple, but academic writing often involves complex sentences where agreement errors can slip in unnoticed. Here’s how to spot and correct them.
“Results” is plural, so the verb should be “show.”
✖ The results of the experiment shows significant improvement.
✔ The results of the experiment show significant improvement.
2. Run-on sentences
Run-on sentences occur when two or more independent clauses are joined incorrectly. Without the proper punctuation or conjunctions, these sentences become confusing and overwhelming. Clarity begins with knowing where one thought ends and another begins.
Two independent clauses need punctuation and/or a conjunction.
✖ The theory was widely accepted it lacked empirical support.
✔ The theory was widely accepted, but it lacked empirical support.
3. Using informal language or contractions
Academic writing demands a formal tone. Using casual language or contractions (like don’t or won’t) can make your work seem unpolished or too conversational. Aim for a professional, objective, and respectful tone of the subject matter.
Avoid contractions and informal expressions in academic writing
✖ The study didn’t prove anything new.
✔ The study did not provide any new findings.
4. Redundant phrasing and wordiness
Less is often more in academic writing. Repeating the same idea or using more words than necessary can weaken your argument and tire your reader. Clarity and conciseness help maintain focus and impact.
“In the event that” and “again” are unnecessary
✖ In the event that the experiment fails, we will repeat it again.
✔ If the experiment fails, we will repeat it.
5. Citation and referencing errors
Even the most compelling arguments can fall flat if sources aren’t cited correctly. Inconsistent or incorrect citation styles reduce credibility and can lead to accusations of plagiarism. Attention to detail is essential here.
Citations must follow a consistent and accurate format
✖ According to Smith, climate change is real (2019).
✔ According to Smith (2019), climate change is real.
6. Unnecessary or missing comma
Commas may be small, but they carry a lot of weight. Misplacing or omitting them can alter the meaning of a sentence or make it hard to follow. Knowing where to pause—and where not to—is crucial for clarity.
Introductory phrases often require a comma
✖ Before conducting the survey the researchers obtained approval.
✔ Before conducting the survey, the researchers obtained approval.
7. Unnecessary or missing capitalization
Capitalization errors often stem from over-correction or misunderstanding what counts as a proper noun. Academic writing requires consistency, and excessive or omitted capital letters can be distracting.
Capitalize proper nouns, not general terms
✖ The University conducted a study on student government in nigeria.
✔ The university conducted a study on student government in Nigeria.
8. Unnecessary or missing hyphen
Hyphens help clarify meaning, especially in compound adjectives. Without them, phrases can become ambiguous or grammatically incorrect. Understanding when to hyphenate improves both readability and precision.
Compound adjectives before nouns often require a hyphen
✖ The study used a well known method.
✔ The study used a well-known method.
9. Spelling and typos
Even the strongest arguments can be undermined by a simple typo or misspelled word. While spellcheck helps, it doesn’t catch everything—especially homophones or context-specific errors. Always proofread carefully.
Spellcheck doesn’t catch everything—proofread carefully
✖ The researchers recieved unexpected results.
✔ The researchers received unexpected results.
10. Improper use of prepositions
Some verbs require specific prepositions
✖ The results were consistent to previous studies.
✔ The results were consistent with previous studies.
|
VERB |
CORRECT preposition |
EXAMPLE SENTENCE |
|---|---|---|
|
Depend |
on |
The results depend on the sample size. |
|
Consist |
of |
The group consists of five participants. |
|
Comply |
with |
All researchers must comply with ethical guidelines. |
|
Focus |
on |
This study focuses on adolescent behavior. |
|
Contribute |
to |
This research contributes to the existing literature. |
|
Succeed |
in |
The experiment succeeded in proving the hypothesis. |
|
Interfere |
with |
Noise can interfere with signal clarity. |
11. Wrong word choice or form
Words like affect/effect or then/than are often confused. Choosing the wrong form can confuse your reader or alter your intended message. Careful word choice enhances clarity and professionalism.
“Affect” is a verb; “effect” is usually a noun.
✖ The new policy had a positive affect on productivity.
✔ The new policy had a positive effect on productivity.
12. Faulty sentence structure
Academic writing thrives on strong, well-formed sentences. When sentence structure breaks down—due to poor punctuation, misplaced clauses, or incomplete thoughts—your ideas lose coherence and power.
Incomplete or improperly joined clauses disrupt clarity
✖ Although the sample size was small. The results were valid.
✔ Although the sample size was small, the results were valid.
13. Confusing homophones
Words that sound the same but have different meanings—like their, there, and they’re—can easily trip up even experienced writers. These errors stand out in academic writing and should be carefully avoided.
Homophones sound the same but have different meanings
✖ Their going to present there research in the next meeting.
✔ They’re going to present their research in the next meeting.
|
Homophone |
Homophone Examples |
|---|---|
|
Their / There / They’re |
Their (possessive pronoun): The researchers presented their findings at the conference. (Belongs to them) There (adverb/place): The lab is located over there, near the main entrance. (Refers to a location or place). They’re (contraction of they are): They’re conducting interviews all week. |
|
Its / It’s |
Its (possessive pronoun): The company updated its cybersecurity policy. (Belongs to them) It’s (contraction of it is or it has): It’s important to cite all your sources. |
14. Faulty parallelism
Parallel structure means expressing ideas in a balanced, consistent way. When elements in a list or comparison don’t match grammatically, the result is jarring and unprofessional. Parallelism brings harmony to your writing.
Lists should maintain a consistent grammatical structure
✖ The study aimed to collect data, analyzing trends, and to draw conclusions.
✔ The study aimed to collect data, analyze trends, and draw conclusions.
15. Vague pronoun reference
Pronouns should clearly refer to a specific noun. When it’s unclear what “it,” “they,” or “this” is referring to, the reader may get lost. Clear pronoun use is essential for reader comprehension.
Avoid unclear references – who was confused?
✖ When the researchers interviewed the participants, they were confused.
✔ The participants were confused when the researchers interviewed them.
16. Dangling modifiers
Modifiers should describe the word they are intended to modify. When they’re left “dangling,” they create confusion or unintended meanings. Careful sentence construction prevents these grammatical missteps.
The subject must logically follow the modifier
✖ After reading the article, the conclusion was unclear.
✔ After reading the article, I found the conclusion unclear.
Modifier: After reading the article (describes when the action occurred) Subject: I found (describes who took the action)
17. Unnecessary or missing apostrophe
Apostrophes show possession or form contractions. Misplacing them—like confusing its and it’s—is a standard and noticeable error in academic writing. Knowing the rules helps maintain credibility.
“It’s” = it is. “its” is possessive – The university updated its online learning platform.
✖ Its a common issue in student writing.
✔ It’s a common issue in student writing.
18. Sentence fragments
A complete sentence needs a subject and a verb. Sentence fragments, often masquerading as full sentences, can disrupt the flow of your writing and weaken your argument. Watch out for these incomplete thoughts.
Fragments often result from dependent clauses left incomplete.
✖ Because the study lacked sufficient data.
✔ The conclusions were limited because the study lacked sufficient data.
19. Confusion between “that” and “which” Sentence fragments
Though they seem interchangeable, “that” and “which” serve different grammatical roles. Choosing the wrong one can affect sentence clarity and meaning. Knowing the distinction sharpens your writing.
Use “that” for essential clauses, “which” for nonessential ones, with commas
✖ The survey which was conducted online had a 60% response rate.
✔ The survey that was conducted online had a 60% response rate.
|
Determining if a Clause is Essential or Non-Essential |
|---|
|
✔ Test if the sentence still makes sense without the clause.
|
|
✔ Ask: Is the clause adding extra information or narrowing it down?
|
20. Overuse of passive voice
While the passive voice has its place, overusing it can make writing vague and impersonal. Academic writing often benefits from an active voice, which provides clarity and emphasizes the agent of action.
Use active voice when clarity and agency are important
✖ The experiment was conducted by the team, and data was analyzed.
✔ The team conducted the experiment and analyzed the data.
21. Summary
Strong academic writing isn’t just about big ideas—it’s also about precision, clarity, and credibility. As this blog has shown, even small grammatical mistakes—like a misplaced comma, a vague pronoun, or a confused homophone—can weaken otherwise powerful arguments.
By becoming familiar with these 20 common errors and learning to spot and correct them, writers can elevate their work and communicate more effectively. Whether you’re a student, researcher, or lifelong learner, mastering these fundamentals will help ensure your writing reflects the quality of your thinking.
Remember: Great writing isn’t just written—it’s proofread and revised.
If you have any questions, please drop a comment below, and we will answer as soon as possible. We also recommend you to refer to our other blogs on academic writing tools, academic writing resources, academic writing phrases and research paper examples which are relevant to the topic discussed in this blog.
