Ed Journey — Study Techniques Guide | edjourney.org
The forgetting-curve retention table in full, plus a side-by-side comparison of re-reading, active recall and spaced review.
Hermann Ebbinghaus measured the forgetting curve in 1885: without review, memory of learned material falls steeply in the first days. His published figures put retention near 58 percent after 20 minutes, about 44 percent after an hour, about 34 percent after one day, about 25 percent after 6 days and about 21 percent after 31 days.
Those five data points are the reason a study schedule needs reviews at all. If you do nothing, a third of what you learned is gone by tomorrow and only a fifth survives to the end of the month.
Re-reading is the default habit because it is low-effort and feels fluent. The testing effect shows the opposite: active recall — closing the book and pulling the answer out of memory — strengthens memory more than re-reading the same material.
On narrow screens, swipe or scroll the plate sideways.
Spaced review combines the two levers. The spacing effect says the same study time spread over days beats massed cramming, so a session at day 1 plus a session at day 7 retains more than the same two hours spent back to back.
Interleaving is the third method worth adding: mixing related topics within one session instead of finishing one topic before the next improves later discrimination between problem types.
Pick from the table by what you need weeks later, not by what feels productive today.
Further reading