Readers judge your writing by your control of certain conventions, which may change depending on your audience, purpose, and writing situation.

For example, your instructor may or may not mark errors in your paper if they’re more concerned with its argument or structure than with sentence-level correctness; they could also decide an error is not serious. Some instructors may even see the errors listed below as stylistic options.

However, a large-scale study by Andrea Lunsford and Karen Lunsford (2008) found that these errors are the most likely to attract readers’ negative attention. Before handing in your papers, proofread them carefully for these errors, which are illustrated below in the sentences in italics.

The Top 25 Grammar Mistakes

Wrong Word

Wrong word errors can convey a slightly different meaning than intended (compose instead of comprise) or a completely wrong meaning (prevaricate instead of procrastinate). They may also be as simple as a wrong preposition or other type of wrong word in an idiom.

Examples:

Did you catch my illusion to the Bible? (“illusion” should be “allusion”)

Edmund Spenser’s The Faerie Queene is a magnificent sixteenth-century allergy. (“allergy” should be “allegory”)

Missing Comma after an Introductory Element

Use a comma after every introductory element—whether word, phrase, or clause—to clarify where it ends and the rest of the sentence begins.

Example:

 Determined to make their flight on time they rose at dawn. (Add a comma after “time”)

Incomplete or Missing Documentation

Always cite your sources to avoid plagiarism, following the documentation style relevant to your discipline.

Examples:

The Social Media Bible defines social media as the “activities, practices, and behaviors among communities of people who gather online to share information, knowledge, and opinions using conversational media.” (Include page number)

According to one source, it costs almost twice an employee’s salary to recruit and train a replacement. (Identify the source)

Vague Pronoun Reference

   A pronoun should refer clearly to its antecedent.

Examples:

If you put this handout in your binder, it may remind you of important tutoring strategies. (“it” is vague)

The authoritarian school changed its cell phone policy, which many students resisted. (Clarify what “which” refers to)

Spelling

Spell checkers cannot catch every error, so proofread for homonyms, compound words, and proper nouns.

Examples:

  Vladimir Putin is the controversial leader of Russia. (“Vladmir” should be “Vladimir”)

  Every where she walked, she was reminded of him. (“Every where” should be “Everywhere”)

Mechanical Error with a Quotation

Ensure quotation marks are used correctly and that punctuation is placed properly within quotes.

Example:

“A woman must have money and a room of her own if she is to write fiction”, Virginia Woolf argues.* (Comma should be inside the quotation marks)

Unnecessary Comma

Avoid using commas where they are not needed, such as before restrictive elements, coordinating conjunctions not joining compound sentences, and between parts of a sentence that are closely related.

Examples:

Many children, of working parents, walk home from school by themselves.* (Remove commas around “of working parents”)

This social scourge can be seen in urban centers, and in rural outposts.* (Remove comma before “and”)

Unnecessary or Missing Capitalization

Capitalize proper nouns, the first words of sentences, and important words in titles, but avoid unnecessary capitalization.

Example:

Financial Aid is a pressing concern for many University Students. (“Financial Aid” and “University Students” should not be capitalized)

Missing Word and Mixing up Similar Words

Carefully proofread to catch omitted words, especially in complex sentences and quotations.

Example:

Soccer fans the globe rejoiced when the striker scored the second goal.(Add “around” after “fans”)

Commonly confused pairs include affect/effect, except/accept, lose/loose, assure/insure/ensure, and compliment/complement.

Affect vs. Effect:

Affect: verb, “to influence.”

“The storm affected over 300 houses.”

Effect: noun, “the result.”

“Taking illegal drugs can have fatal effects.”

Except vs. Accept:

Except: preposition, “not including.”

“Everyone got a Valentine’s Day card except me.”

Accept: verb, “to receive.”

“Did you accept the payment?”

Lose vs. Loose:

Lose: verb, “to misplace.”

“Did you lose your homework again?”

Loose: adjective, “not tight.”

“My shoelaces are loose.”

Assure vs. Insure vs. Ensure:

Assure: verb, “to guarantee.”

“I assure you that I’ve never met her.”

Insure: verb, “to provide insurance.”

“We need to insure our new house.”

Ensure: verb, “to make certain.”

“Ensure the lights are off before you leave.”

Compliment vs. Complement:

Compliment: verb/noun, “to praise”/“an expression of praise.”

“He complimented my dress.”/“She gave me a compliment.”

Complement: verb/noun, “to complete or enhance”/“something that completes or enhances.”

“These shoes complement my outfit.”/“The scarf is a perfect complement to the dress.”

Faulty Sentence Structure

Maintain a consistent structure within a sentence.

Example:

The information that families have access to is what financial aid is available and thinking about the classes available, and how to register.* (Revise for parallel structure)

Missing Comma with a Nonrestrictive Element

 Use commas to set off nonrestrictive phrases and clauses.

Example:

David who loved to read history was the first to head to the British Library. (Add commas around “who loved to read history”)

Unnecessary Shift in Verb Tense

Keep verb tenses consistent unless a change is necessary for clarity.

Example:

Martin searched for a great horned owl. He takes photographs of all the birds he sights. (“searched” and “takes” should be in the same tense)

Missing Comma in a Compound Sentence

  Use a comma before coordinating conjunctions in compound sentences.

Example:

Miranda drove her brother and her mother waited at home. (Add comma before “and”)

Unnecessary or Missing Apostrophe

Use apostrophes to show possession and form contractions correctly.

Examples:

Repeated viral infections compromise doctors immune systems. (“doctors” should be “doctors'”)

The chef lifted the skillet off it’s hook. Its a fourteen-inch, copper skillet. (“it’s” should be “its” and “Its” should be “It’s”)

Fused (Run-on) Sentence

Correct run-on sentences by adding punctuation or connecting words.

A run-on sentence contains multiple independent clauses that aren’t properly joined with punctuation or conjunctions. These sentences can be confusing and hard to read.

Examples:

The house was flooded with light, the moon rose above the horizon. (Add a period or conjunction)

He wondered what the decision meant he thought about it all night. (Add punctuation or conjunction)

Incorrect: “We went to the movie theater today; we saw a comedy about two people getting into scrapes.”

How to Fix:

Option 1: Break the sentence into two. “We went to the movie theater today. We saw a comedy about two people getting into scrapes.”

Option 2: Add a conjunction. “We went to the movie theater today, where we saw a comedy about two people getting into scrapes.”

Option 3: Use an em-dash. “We went to the movie theater today—we saw a comedy about two people getting into scrapes.”

Comma Splice

   Fix comma splices by adding appropriate punctuation or conjunctions.

Example:

The students rushed the field, they tore down the goalposts.(Use a period, semicolon, or conjunction)

Lack of Pronoun/Antecedent Agreement

   Ensure pronouns agree with their antecedents in number and gender.

Example:

Every guest left their shoes at the door. (“their” should be “his or her” or revise to use a plural antecedent)

Poorly Integrated Quotation

   Integrate quotations smoothly and logically into your writing.

Examples:

An award-winning 2009 study of friendship “understanding social networks allows us to understand how indeed, in the case of humans, the whole comes to be greater than the sum of its parts” (Christakis and Fowler 26). (Rephrase to integrate the quotation better)

 “Social networks are intricate things of beauty” (Christakis and Fowler xiii). Maintaining close friendships is good for your health. (Introduce the quotation properly)

Missing or Unnecessary Hyphen

   Use hyphens in compound adjectives when necessary and avoid hyphenating two-word verbs.

Examples:

This article describes eighteenth century theater. (“eighteenth century” should be “eighteenth-century”)

The dealers want to buy-back the computers and refurbish them. (“buy-back” should be “buy back”)

Sentence Fragment

   Ensure each sentence is complete with a subject and verb, and avoid fragments.

Examples:

The American colonists resisted British taxation. And started the American Revolution.* (“And started the American Revolution” is a fragment)

The pink geranium blooming in its pot.* (Add a verb to complete the sentence)

We visited the park. Where we threw the Frisbee.* (Combine the fragment with the preceding sentence)

Mixing Up Homonyms

Homonyms sound the same but have different meanings and spellings.

Common Homonyms:

There, Their, They’re:

There: location. “Put the book over there.”

Their: possessive pronoun. “Their car is red.”

They’re: contraction of “they are.” “They’re going to the park.”

Your, You’re:

Your: possessive pronoun. “Your cat is cute.”

You’re: contraction of “you are.” “You’re going to love this movie.”

To, Too, Two:

To: preposition, used to express motion or direction. “We are going to the store.”

Too: adverb, meaning “also” or “excessively.” “I want to go too.” / “It’s too hot.”

Two: the number 2. “I have two apples.”

Mixing Up “Between” and “Among”

Use between for distinct, individual items; use among for items that are part of a group.

Incorrect: “There’s an intense rivalry among these two schools.”

Correct: “There’s an intense rivalry between these two schools.”

Inconsistent Verb Tenses

Maintain the same verb tense within a sentence or narrative.

Incorrect: “I wake up in the morning and grabbed a bite to eat.”

Correct: “I wake up in the morning and grab a bite to eat.” (present tense)

Correct: “I woke up in the morning and grabbed a bite to eat.” (past tense)

Incomplete Comparisons

Complete comparisons to clarify what you are comparing.

Incorrect: “I’m much happier now.”

Correct: “I’m much happier now than I was in college.”

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