Common Grammar Mistakes in Student Essays and How to Fix Them

Introduction: Understanding the Impact of Grammar Errors

Grammar mistakes can significantly undermine the quality and effectiveness of student essays. Even brilliant ideas can lose their impact when presented with poor grammar, causing professors to focus on errors rather than content. According to a study by the National Assessment of Educational Progress, approximately 74% of high school seniors make consistent grammar mistakes in their academic writing. By identifying and correcting these common errors, students can dramatically improve their writing quality and academic performance.

The Most Common Grammar Mistakes Students Make

Subject-Verb Agreement Errors

Subject-verb agreement errors occur when the subject and verb don’t match in number (singular or singular, plural or plural). This fundamental grammatical rule trips up many students, especially when sentences become complex.

Examples of subject-verb agreement errors:

Incorrect	Correct
The group of students were late.	The group of students was late.
Neither of the essays are finished.	Neither of the essays is finished.
Everyone in the dorms have their own study habits.	Everyone in the dorms has their own study habits.

Professor James Williams of Columbia University notes that “subject-verb agreement errors are among the most common mistakes I see, even in papers from otherwise strong writers.” The error often happens with collective nouns or when the subject and verb are separated by other words.

Sentence Fragments

Sentence fragments are incomplete thoughts presented as complete sentences. They typically lack a subject, a verb, or both, and cannot stand alone.

Examples of sentence fragments:

Fragment	Corrected Sentence
Because I was late to class.	Because I was late to class, I missed the quiz.
Running through the library.	She was running through the library.
Without considering the consequences.	He acted without considering the consequences.

Dr. Emily Chen, writing instructor at Stanford University, explains that “fragments often occur when students are transitioning between ideas or when they’re rushing through their writing process.”

Run-on Sentences

Run-on sentences occur when two or more independent clauses are joined without proper punctuation or connecting words. These sentences can confuse readers and dilute the impact of your arguments.

Examples of run-on sentences:

Run-on Sentence	Corrected Version
The professor assigned the essay we have to complete it by Friday.	The professor assigned the essay, and we have to complete it by Friday.
I studied all night I still failed the test.	I studied all night, but I still failed the test.
She is an excellent writer her essays always receive A grades.	She is an excellent writer; her essays always receive A grades.

“Run-on sentences indicate that a student hasn’t fully grasped how to express complex ideas in writing,” observes Dr. Michael Robertson at Princeton Writing Center.

Comma Splices

A comma splice occurs when two independent clauses are joined with only a comma. This is considered a serious grammatical error in academic writing.

Examples of comma splices:

Comma Splice	Corrected Version
The assignment was difficult, I worked on it for days.	The assignment was difficult; I worked on it for days.
She completed her research paper, she submitted it early.	She completed her research paper, and she submitted it early.
I need to improve my writing skills, this course will help me.	I need to improve my writing skills. This course will help me.

Misuse of Apostrophes

Apostrophes are commonly misused in student writing, particularly when forming possessives and contractions.

Common apostrophe errors:

Incorrect	Correct	Explanation
The students’ book	The student’s book	For singular possession
The class’s projects	The class’ projects	For singular nouns ending in s
Its going to be difficult	It’s going to be difficult	Confusion between its (possessive) and it’s (contraction)
In the 1990’s	In the 1990s	Apostrophe not needed for pluralizing decades

Punctuation Problems That Plague Student Essays

Misplaced or Missing Commas

Commas serve various purposes in writing, from separating items in a list to setting off introductory elements. Misplacing or omitting commas can change the meaning of sentences or create confusion.

Common comma errors:

Incorrect	Correct
After completing the experiment the students recorded their observations.	After completing the experiment, the students recorded their observations.
The professor who teaches Latin is retiring this year.	The professor, who teaches Latin, is retiring this year. (If providing additional information about the only professor)
We studied biology chemistry and physics.	We studied biology, chemistry, and physics.

Dr. Lisa Thompson, editor of the Journal of Academic Writing, points out that “comma usage reflects a writer’s understanding of sentence structure and rhythm. Proper comma placement can dramatically improve readability.”

Semicolon and Colon Confusion

Many students struggle with the proper use of semicolons and colons, often using them interchangeably or avoiding them altogether.

Guidelines for semicolons and colons:

Punctuation	Primary Use	Example
Semicolon (;)	Connecting related independent clauses	The research was comprehensive; it covered all aspects of the topic.
Colon (:)	Introducing a list, explanation, or quotation	The essay had three main components: introduction, body, and conclusion.

According to The Chicago Manual of Style, semicolons and colons are among the most misunderstood punctuation marks in academic writing.

Verb Tense Consistency Issues

Maintaining consistent verb tenses throughout an essay is crucial for clarity. Shifts in tense without logical reason can confuse readers and undermine the professionalism of your writing.

Examples of tense inconsistency:

Inconsistent	Consistent
Shakespeare wrote many plays and has created memorable characters.	Shakespeare wrote many plays and created memorable characters.
When I entered the library, I am amazed by the collection of books.	When I entered the library, I was amazed by the collection of books.
The researcher conducts the experiment and recorded the results.	The researcher conducted the experiment and recorded the results.

Harvard University’s writing center recommends that students “map out the timeline of their essay before writing to ensure logical tense progression.”

Word Choice and Usage Errors

Commonly Confused Words

Certain word pairs or groups are frequently confused due to similar spelling, pronunciation, or meaning.

Most commonly confused words in student essays:

Confused Words	Correct Usage
Their/There/They’re	Their = possessive; There = location; They’re = they are
Your/You’re	Your = possessive; You’re = you are
Affect/Effect	Affect = verb (to influence); Effect = noun (result)
To/Too/Two	To = direction; Too = also/excessively; Two = number
Then/Than	Then = time sequence; Than = comparison

Professor Robert Johnson of Yale University states, “Word confusion errors signal to professors that a student hasn’t proofread carefully, regardless of the content’s quality.”

Improper Homophone Usage

Homophones are words that sound the same but have different meanings and spellings. These frequently cause errors in student writing.

Common homophone errors:

Incorrect	Correct
The research had a positive affect.	The research had a positive effect.
I will loose points for grammar mistakes.	I will lose points for grammar mistakes.
The professor complemented my essay.	The professor complimented my essay.
We need to except these limitations.	We need to accept these limitations.

Strategies for Identifying and Correcting Grammar Mistakes

Effective Proofreading Techniques

• Read your work aloud: This helps identify awkward phrasing and missing words.
• Proofread backward: Start from the last sentence and move to the first to focus on individual sentences.
• Take a break before proofreading: Return with fresh eyes after at least a few hours.
• Focus on one type of error at a time: Make multiple proofreading passes, each time looking for a specific type of error.
• Use a ruler or blank page: Cover everything except the line you’re currently reading to maintain focus.

Grammar Checking Tools: Benefits and Limitations

Modern technology offers various tools to help students identify grammar mistakes, but understanding their limitations is crucial.

Tool Type	Benefits	Limitations
Built-in word processor tools	Convenient, free	Miss context-dependent errors
Free online grammar checkers	Easy access, basic checks	Limited features, may miss complex errors
Premium grammar software	Comprehensive checks, explanations	Cost, may create over-reliance
AI writing assistants	Real-time feedback, improvement suggestions	May not understand specialized terminology or unique writing styles

Dr. Patricia Greenfield, a linguistics professor at UCLA, cautions that “grammar checkers should be viewed as assistants, not replacements for learning grammar rules. Students still need to understand why something is an error.”

The Value of Peer Review and Writing Centers

Getting feedback from others can significantly improve your writing quality. Most universities offer writing centers where trained tutors can help identify and explain grammar mistakes.

Benefits of writing center consultations:

• Personalized feedback tailored to your specific writing challenges
• Explanations of grammar rules in context of your own writing
• Development of self-editing skills
• Support throughout the writing process, not just at the end

A study published in the Journal of Writing Research found that students who regularly visited writing centers showed a 32% greater reduction in grammar errors compared to those who relied solely on self-editing.

FAQ: Common Questions About Grammar in Student Essays