No topic in ELA is more contentious than grammar instruction. Some teachers believe that grammar is the foundation of good writing and that students cannot write well without mastering the parts of speech, sentence diagramming, and the full range of conventions. Others argue that grammar instruction is a time waster that does nothing to improve student writing and that time spent on grammar drills would be better spent on actual writing practice. The research suggests that both extreme positions are wrong. Some grammar instruction matters significantly. Other grammar instruction has minimal impact on writing quality.

A major meta-analysis of grammar research published in 2025 found that isolated grammar instruction (teaching grammar rules out of context through worksheets and exercises) has almost no effect on student writing quality. That is the bad news for grammar-heavy curricula. The good news is that contextualized grammar instruction, teaching grammar within the context of a student's own writing, has moderate to strong effects on writing quality. The difference is profound: teaching a student the definition of a sentence fragment produces no improvement in their writing. Teaching a student to identify and fix a sentence fragment in their own essay produces measurable improvement.

Which grammar issues should you prioritize? Focus on the errors that actually interfere with meaning or that appear frequently in your students' writing. Sentence fragments and run-ons affect clarity. Subject-verb disagreement affects clarity. Misplaced modifiers can confuse the reader. Vague pronoun reference can confuse the reader. These are worth teaching in context because they interfere with communication. Comma splices, excessive passive voice, and prepositions at the end of sentences are less important because they rarely prevent understanding. Strict adherence to formal conventions like 'never split an infinitive' or 'never end a sentence with a preposition' is not worth teaching because professional writers regularly break these rules intentionally for effect.

Prioritizing Grammar Teaching

• Focus grammar instruction on the errors that appear in your specific students' writing, not on every possible grammar rule.
• Teach grammar in the context of student writing: identify the error in the student's draft and teach the rule using their sentence, not a textbook example.
• Use whole-class mini-lessons for common errors (if 80 percent of your students are making the same mistake, it is worth a five-minute lesson) and individual feedback for idiosyncratic errors.
• Distinguish between 'this is a violation of a formal rule' and 'this will confuse the reader.' Teach the second category seriously. The first category can be taught more lightly.
• Know the difference between an error that a student makes because they do not understand the rule (teaching is appropriate) and an error that a student makes because they do not proofread (teaching will not help; they need a proofreading strategy).

AI and Grammar Teaching

Grammar checking has become part of the baseline tools students use. Built-in grammar checkers in word processors, browser extensions, and dedicated software like Grammarly catch many standard errors automatically. This shift changes what teachers should teach. Students do not need to be taught to check for comma splices if their word processor highlights them automatically. What students do need is the judgment to override the grammar checker when doing so is appropriate and the understanding of why a grammar rule exists so they can make intentional choices about when to follow it and when to break it.

Rather than teaching grammar rules, consider teaching grammar judgment: the ability to recognize when a grammatical choice sounds wrong, when a rule exists for a reason versus when it is arbitrary, and when breaking the rule intentionally is an effective stylistic choice. That is the grammar instruction that actually improves writing, and it is quite different from the grammar instruction that most textbooks offer.