Why Grammar Still Matters

Grammar errors don't just cost you marks — they distract the reader from your ideas. Even a well-argued essay loses credibility when it's riddled with punctuation mistakes or unclear sentences. The good news is that most grammar errors students make are predictable and easy to fix once you know what to look for.

Here are the ten most common grammar mistakes in student essays, with examples and corrections.

1. Run-On Sentences

The mistake: Joining two independent clauses with just a comma, or without any punctuation at all.

Incorrect: "The experiment failed, the results were inconclusive."

Correct: "The experiment failed; the results were inconclusive." Or: "The experiment failed because the results were inconclusive."

2. Comma Splices

Similar to run-ons, a comma splice uses a comma where a stronger break is needed. Fix it with a semicolon, a full stop, or a coordinating conjunction (for, and, nor, but, or, yet, so).

3. Apostrophe Errors

The mistake: Confusing possessives and plurals, or misusing "it's" and "its."

  • Its = possessive ("The dog wagged its tail.")
  • It's = it is ("It's a difficult problem.")
  • Plurals don't need apostrophes: "the 1980s" not "the 1980's"

4. Inconsistent Tense

Switching between past and present tense mid-essay confuses the reader. Choose one tense and stick to it. When writing about literature, use the literary present tense ("Shakespeare writes…", not "Shakespeare wrote…").

5. Vague Pronoun Reference

When "it," "this," or "they" doesn't clearly refer to a specific noun, the sentence becomes confusing.

Vague: "The government introduced the policy, but they didn't explain it clearly."

Clearer: "The government introduced the policy but did not explain its implications clearly."

6. Subject-Verb Agreement Errors

The verb must agree with its subject in number — singular subject, singular verb.

Incorrect: "The team of researchers are publishing their findings."

Correct: "The team of researchers is publishing its findings." (Team is singular.)

7. Misplaced or Dangling Modifiers

A modifier should sit next to the word it describes. When it doesn't, you get a dangling modifier.

Incorrect: "Running through the park, the flowers looked beautiful."

Correct: "Running through the park, she noticed the flowers looked beautiful."

8. Using "However" Without Correct Punctuation

"However" is a conjunctive adverb, not a conjunction. When it connects two sentences, use a semicolon before it and a comma after.

Incorrect: "The policy was popular, however it had flaws."

Correct: "The policy was popular; however, it had flaws."

9. Overusing Passive Voice

Passive voice isn't wrong, but overusing it makes your writing weak and indirect.

Passive: "The essay was written by the student."

Active: "The student wrote the essay."

Use active voice as your default. Reserve passive voice for situations where the "doer" is unknown or unimportant.

10. Wordiness and Filler Phrases

Cut phrases that add length without meaning:

  • "Due to the fact that" → because
  • "In order to" → to
  • "At this point in time" → now
  • "It is important to note that" → (just say the thing)

Your Pre-Submission Grammar Checklist

  1. Read your essay aloud — awkward sentences are easier to catch when spoken.
  2. Check every sentence has a clear subject and verb.
  3. Scan specifically for apostrophes, commas, and tense consistency.
  4. Use your word processor's grammar checker as a starting point — but don't rely on it alone.
  5. Ask someone else to read it — a fresh pair of eyes catches errors yours miss.