Run-Ons and Fragments: The Fastest Way to Diagnose “Hard to Follow” Student Writing
Share
Teacher problem: A student has good ideas, but the paragraph is exhausting to read. Often the real issue isn’t “bad writing”—it’s sentence boundaries (run-ons and fragments).
Why sentence boundaries are the fastest clarity diagnosis
When writing feels “hard to follow,” the cause is frequently one of these:
- Run-on risk: too many independent ideas pushed together without clear boundaries
- Fragment risk: a dependent idea standing alone as if it were complete
Fixing sentence boundaries is high-leverage because it improves meaning without rewriting a student’s ideas.
The 60-second teacher diagnosis (before you mark everything)
- Scan for missing end punctuation (especially in long sentences).
- Scan for “because/when/although/which” starts that never return to a complete sentence.
- Look for long sentences with multiple “and/but/so” that may hide comma splices or fused sentences.
High-leverage fixes that keep student ownership
Fix 1: “Find the main clause”
Have the student underline the part with a clear subject + verb. If they can’t, it’s likely a fragment or a tangled run-on.
Fix 2: “Split first, then combine”
If a sentence is a pile-up, split it into two complete sentences first. Then (optionally) recombine one pair with a conjunction once meaning is clear.
Fix 3: “One punctuation rule for today”
Pick one boundary rule to practice (end punctuation, comma splice, or conjunction boundaries). One rule consistently applied beats 10 scattered corrections.
Use the free Student Writing Checker to triage faster
About + How to Interpret Results | Free Teacher Tools Hub
FAQ
Why do run-ons happen so often?
Many students write like they speak. Speech uses pauses and tone; writing needs punctuation and structure to show where ideas begin and end.
Do I mark every run-on and fragment?
No. Identify the pattern and correct 2–4 examples, then assign one targeted revision task (e.g., “fix sentence boundaries in paragraph 2”).
What if the student’s sentences are very long but “technically correct”?
Then it becomes a clarity and control issue. Focus feedback on making the main clause easy to find and reducing overload for the reader.