Homework is one of the most debated routines in education — and one of the most researched. The definitive synthesis, Cooper, Robinson, and Patall's review of research from 1987–2003, offers a clearer picture than the staff-room argument does.
What the Synthesis Found
Two headline findings stand out:
- Homework vs. no homework: across manipulated-assignment studies, students who did homework outperformed those who didn't with a mean effect size of d = 0.60 on unit tests — a meaningful advantage.
- But the payoff depends heavily on age. The correlation between time spent on homework and achievement was near zero for elementary students (r ≈ .06) and meaningfully positive for secondary students (r ≈ .25).
Homework–achievement link by grade level (Cooper et al., 2006)
High school (time-on-task correlation) — r ≈ .25
Middle school — modest positive link
Elementary school (student-reported time) — r ≈ .06
The research doesn't say "no homework in elementary school." It says heavy homework loads in early grades buy little achievement while costing time, play, and family goodwill.
What This Means for Your Assignments
- Younger grades: keep homework short, routine, and reading-centered. Read-alouds and daily reading carry more benefit than worksheet packets.
- Older grades: homework shows real returns — but assignment quality matters: tasks that require thinking, not just copying, earn their time.
- Purpose beats duration. The evidence favors a well-designed 15-minute task over an hour of low-level repetition.
- Watch the equity cost. Cooper's team flagged home environment as a moderator — the same packet is a different task depending on the kitchen table it lands on.
The Takeaway
Homework isn't one thing. Match the dose to the age, make every assignment answer "what does this teach that class time can't," and be suspicious of volume as a proxy for rigor.
