Twelve Common Errors

This list includes brief examples and explanations intended for you to use as reminders while you are editing your papers.

If you would like to learn more, consider:

Taking one of the free grammar, style, and punctuation classes offered by the Writing Center.
Setting up an appointment for an individual conference in the Writing Center.
Conferencing with your course instructor.
Consulting a handbook for additional examples and complete explanations.

1. Sentence Fragments

Make sure each word group you have punctuated as a sentence contains a grammatically complete and independent thought that can stand alone as an acceptable sentence.

Incorrect: Tests of the Shroud of Turin have produced some curious findings. For example, the pollen of forty-eight plants native to Europe and the Middle East.Here, the second “sentence” is a fragment.

Correct: Tests of the Shroud of Turin have produced some curious findings. For example, the cloth contains the pollen of forty-eight plants native to Europe and the Middle East.

Incorrect: Scientists report no human deaths due to excessive caffeine consumption. Although caffeine does cause convulsions and death in certain animals.Here, the second “sentence” is a fragment.

Correct: Scientists report no human deaths due to excessive caffeine consumption, although caffeine does cause convulsions and death in certain animals.

2. Sentence Sprawl

Too many equally weighted phrases and clauses produce tiresome sentences.

Less preferred: The hearing was planned for Monday, December 2, but not all of the witnesses could be available, so it was rescheduled for the following Friday, and then all the witnesses could attend.There are no grammatical errors here, but the sprawling sentence does not communicate clearly and concisely.

Better: The hearing, which had been planned for Monday, December 2, was rescheduled for the following Friday so that all witnesses would be able to attend.

3. Misplaced and Dangling Modifiers

Place modifiers near the words they describe; be sure the modified words actually appear in the sentence.

Incorrect: When writing a proposal, an original task is set for research.Here, “an original task” is the topic of the sentence, but a task can’t write a proposal.

Correct: When writing a proposal, a scholar sets an original task for research.

Incorrect: Many tourists visit Arlington National Cemetery, where veterans and military personnel are buried every day from 9 a.m. until 5 p.m.Here, the phrase “from 9 a.m. until 5 p.m.” is misplaced and incorrectly describes when veterans are buried instead of when tourists visit the cemetery.

Correct: Every day from 9:00 a.m. until 5:00 p.m., many tourists visit Arlington National Cemetery, where veterans and military personnel are buried.

4. Faulty Parallelism

Be sure you use grammatically equal sentence elements to express two or more matching ideas or items in a series.

Incorrect: The candidate’s goals include winning the election, a national health program, and the educational system.Here, “winning the election” is an action, but “a national health program” and “the educational system” are things.

Correct: The candidate’s goals include winning the election, enacting a national health program, and improving the educational system.

Incorrect: Badger fans are not so much disappointed by the loss as the team’s lack of effort.After “not so much … as,” the sentence should compare parallel elements. “Disappointed by the loss” and “the team’s lack of effort” are not parallel in form.

Better: Badger fans are not so much disappointed by the loss as they are by the team’s lack of effort.

5. Unclear Pronouns

All pronouns must clearly refer to definite referents (nouns).

Use it, they, this, that, these, those, and which carefully to prevent confusion.

Unclear: Einstein was a brilliant mathematician. This is how he was able to explain the universe.The reader has to infer what “This” means: Einstein’s brilliance? His mathematical ability? His training as a mathematician? Or something else entirely?

Better: Einstein, who was a brilliant mathematician, used his ability with numbers to explain the universe.

Unclear: Because Senator Martin is less interested in the environment than in economic development, he sometimes neglects it.The sentence is confusing because “it” could refer to either “the environment” or “economic development.”

Better: Because of his interest in economic development, Senator Martin sometimes neglects the environment.

6. Incorrect Pronoun Case

Determine whether the pronoun is being used as a subject, an object, or a possessive in the sentence, and select the pronoun form to match.

Incorrect: Castro’s communist principles inevitably led to an ideological conflict between he and President Kennedy.

Correct: Castro’s communist principles inevitably led to an ideological conflict between him and President Kennedy.

Incorrect: Because strict constructionists recommend fidelity to the Constitution as written, no one objects more than them to judicial reinterpretation.

Correct: Because strict constructionists recommend fidelity to the Constitution as written, no one objects more than they [do] to judicial reinterpretation.

7. Omitted Commas

Use commas to signal nonrestrictive or nonessential material, to prevent confusion, and to indicate relationships among ideas and sentence parts.

Incorrect: When it comes to eating people differ in their tastes.

Correct: When it comes to eating, people differ in their tastes.

Incorrect: The Huns who were Mongolian invaded Gaul in 451.“Who were Mongolian” adds information but does not change the core meaning of the sentence because Huns were a Mongolian people; this material is therefore nonrestrictive or nonessential.

Better: The Huns, who were Mongolian, invaded Gaul in 451.

For more information on commas see Commas: Punctuating Restrictive and Non-restrictive Modifiers and Punctuating Coordinating Conjunctions and Sentence Adverbs, or take one of the free grammar, style, and punctuation workshops offered by the Writing Center.

8. Superfluous Commas

Unnecessary commas can make sentences harder to read.

Incorrect: Field trips are required, in several courses, such as, botany and geology.

Correct: Field trips are required in several courses, such as botany and geology.

Incorrect: The term, “scientific illiteracy,” has become almost a cliche, in educational circles.

Correct: The term “scientific illiteracy” has become almost a cliche in educational circles.

9. Comma Splices

Do not link two independent clauses with a comma (unless you also use a coordinating conjunction: and, or, but, for, nor, so, yet).

Instead use a period or semicolon, or rewrite the sentence.

Incorrect: In 1952 Japan’s gross national product was one third that of France, by the late 1970s it was larger than the GNPs of France and Britain combined.

Correct: In 1952 Japan’s gross national product was one third that of France. By the late 1970s it was larger than the GNPs of France and Britain combined.

Incorrect: Diseased coronary arteries are often surgically bypassed, however half of all bypass grafts fail within ten years.

Correct: Diseased coronary arteries are often surgically bypassed; however, half of all bypass grafts fail within ten years.

10. Apostrophe Errors

Apostrophes indicate possession for nouns (“Jim’s hat,” “several years’ work”) but not for personal pronouns (its, your, their, and whose).

Apostrophes also indicate omissions in contractions (“it’s” = “it is”).

In general, they are not used to indicate plurals.

Incorrect: In the current conflict its uncertain who’s borders their contesting.

Correct: In the current conflict it is [it’s] uncertain whose borders they are [they’re] contesting.

Incorrect: The Aztecs ritual’s of renewal increased in frequency over the course of time.

Correct: The Aztecs’ rituals of renewal increased in frequency over the course of time.

11. Easily Confused Words

“Effect” is most often a noun (the effect), and “affect” is almost always a verb.

Other pairs commonly confused include: lead/led and accept/except.

Check a glossary of usage to find the right choice.

Incorrect: The recession had a negative affect on sales.

Correct: The recession had a negative effect on sales. (or) The recession affected sales negatively.

Incorrect: The laboratory instructor chose not to offer detailed advise.

Correct: The laboratory instructor chose not to offer detailed advice.

12. Misspellings

Since spelling errors can make a paper appear less polished than intended and distract readers from the ideas you’re advancing, careful proofreading is essential. Don’t allow a few minor mistakes to detract from the hard work invested in your project.

In addition to comprehensive dictionaries, you may want to use electronic spell checks, spelling dictionaries, and lists of frequently misspelled words found in handbooks.