If rereading feels easier, isn't it working better?

No — immediate fluency misleads. In the 2006 experiment restudiers looked better at 5 minutes but forgot 56% within 2 days, while retrieval practisers forgot 13%.

How many techniques actually earned a high-utility rating?

Two out of ten. Dunlosky et al. (2013) rated only practice testing and distributed practice as high utility; highlighting, rereading and summarisation were low utility.

What schedule should a beginner use?

Review after 1 day, then 3 days, then 1 week, then 2 weeks. Each slot is a self-test, and failed items move back one interval.

Does spacing mean studying more hours?

No. Cepeda et al. (2006) found spacing the same hours over time beats cramming them; the gain comes from distribution, not volume.

2 of 10techniques rated high utility

56% vs 13%forgetting at 2 days, restudy vs retrieval

254 studiesin the Cepeda spacing review

10techniques reviewed

Test, wait, test again

Droos2 — Spaced Repetition and Retrieval | droos2.com

Two study techniques survived a ten-technique review with a high-utility rating: practice testing and distributed practice. This guide shows the measured numbers behind them and how to fold both into an ordinary week of study.

droos2.com
Spaced repetition & retrieval — a working notebook
A field guide to testing yourself on a schedule

Measured, not estimated

Key numbers

10techniques reviewedDunlosky et al. (2013) rated each of ten common learning techniques for utility.

242 studiesconfirming the rankingDonoghue and Hattie (2021) re-checked the ranking across 242 studies with over 169,000 participants.

1–3–7–14 daysstarter review intervalsA practical first spacing schedule: review after 1 day, then 3 days, then 1 week, then 2 weeks.

Ten techniques, rated

Ten common study techniques by measured evidence rating
Technique	Evidence rating	What the numbers show
Practice testing	High utility	Retrieval practisers forgot 13% at 2 days versus 56% for restudiers
Distributed practice	High utility	Spacing beat cramming across 254 studies and 14,000+ observations
Highlighting	Low utility	Rated low in the ten-technique review
Rereading	Low utility	Restudy group forgot 56% within 2 days
Summarisation	Low utility	Rated low in the ten-technique review
Techniques 6–10	Mixed / intermediate	Ranking confirmed across 242 studies with 169,000+ participants

Ten common study techniques by measured evidence rating

What do spaced repetition and retrieval practice actually do?

They fight forgetting from two directions: retrieval strengthens the memory now, spacing keeps it strong later.

Retrieval practice means pulling information out of memory — a closed-book self-test, a blank-page recall, a set of questions answered from scratch — instead of putting it back in by rereading. The act of successful recall is what changes the memory.

Spaced repetition means spreading the same total study hours across days and weeks rather than massing them into one block. The material is met more than once, with gaps that force a partial forgetting and a fresh retrieval each time.

The two combine naturally: a spaced schedule is just a timetable of retrieval sessions. The evidence for each is separate, but the practical routine is one loop — test, wait, test again.

Retrieval: answer questions or write from memory with the notes closed.
Spacing: keep total hours fixed but distribute them over days.
Combine: each spaced slot becomes a self-test, not a reread.

Terms used on this page

Retrieval practice: Recalling information from memory without looking at the source, for example by answering questions or writing from a blank page.
Distributed practice: Spreading study of the same material across multiple sessions over time instead of massing it into one block.
Spacing interval: The gap between two review sessions on the same material, such as 1 day or 1 week.
Forgetting curve: The pattern in which recall drops fastest in the first hours and days after learning, then levels off.
High-utility technique: A study method rated as broadly effective and worth adopting in the Dunlosky et al. (2013) review of ten techniques.

Questions visitors actually ask

If rereading feels easier, isn't it working better?: No — immediate fluency misleads. In the 2006 experiment restudiers looked better at 5 minutes but forgot 56% within 2 days, while retrieval practisers forgot 13%.
How many techniques actually earned a high-utility rating?: Two out of ten. Dunlosky et al. (2013) rated only practice testing and distributed practice as high utility; highlighting, rereading and summarisation were low utility.
What schedule should a beginner use?: Review after 1 day, then 3 days, then 1 week, then 2 weeks. Each slot is a self-test, and failed items move back one interval.
Does spacing mean studying more hours?: No. Cepeda et al. (2006) found spacing the same hours over time beats cramming them; the gain comes from distribution, not volume.

How this guide was assembled

The page compiles findings from the named reviews and experiments only: Dunlosky et al. (2013), Roediger and Karpicke (2006), Cepeda et al. (2006), Donoghue and Hattie (2021) and Ebbinghaus (1885). No original data was collected.

Sources

Each figure on this page traces to one of the studies listed in the timeline.