Why do you forget MCQs you have already done?
The short answer
Because re-reading builds recognition and exams demand recall, and because you almost certainly revised too soon. Two changes fix most of it and neither costs extra hours: test yourself instead of re-reading, and revisit a chapter after a gap long enough that recall is difficult. Difficulty during revision is the signal that it is working, which is why the comfortable method is the ineffective one.
Why does re-reading feel like it works when it does not?
Because it makes the material fluent, and your brain reads fluency as mastery. The second time through a chapter, nothing surprises you, everything follows, and the whole thing feels understood. That feeling is generated by the page being in front of you.
In the exam hall the page is not in front of you. You have to produce the answer from nothing, which is a different operation from confirming an answer you can see, and it is the only operation the paper tests. This is the single most common study mistake, and it is common precisely because it feels so much better than the alternative.
The check
Close the book and write down what the chapter contained. If you cannot, you did not know it a moment ago either; you were reading it. This is uncomfortable the first few times and it is the fastest diagnostic you have.
When should you revise a chapter again?
Later than feels right. Revising the day after you studied is nearly free, because nothing has been forgotten yet and nothing has to be reconstructed, and it is the reconstruction that strengthens the memory.
The useful moment is when recall has become effortful but is still possible. That is roughly a week for material you have just met and roughly a month for material you have already revisited successfully. The exact numbers matter far less than the principle: increasing gaps, not daily repetition.
| When | What you do | How it should feel |
|---|---|---|
| Day 0 | Read the chapter, then do its questions untimed | New and slow |
| Day 2 or 3 | Redo only the questions you got wrong | Familiar, some gaps |
| About a week later | Redo the whole chapter's questions without opening the book first | Effortful. This is the point. |
| About a month later | Mixed practice including this chapter | Mostly automatic |
| Two weeks before the paper | Timed mixed practice across every chapter | Fast, and about pacing rather than content |
Struggling to recall is not failure
Students abandon spacing because the week-later session feels bad compared with the day-after session. The difficulty is the mechanism, not a sign that the first pass was wasted. Easy revision is revision that changes nothing.
Why are MCQs a study tool rather than only a test?
Because attempting a question forces retrieval, and retrieval is what strengthens memory. A question you struggled with and then got right is worth several passes of re-reading the same content, which makes an MCQ bank a genuinely efficient way to learn rather than only a way to check.
- Attempt before you read the explanation, always. Reading the explanation first turns an exercise in retrieval into an exercise in reading.
- Read the explanation even when you were right. A correct guess and a correct answer look identical on a score sheet and are not the same thing.
- Do not repeat a chapter the same day you finished it. You will score well and learn little.
- Mix chapters once you have covered a few. Real papers do not warn you which chapter a question comes from, and picking the right method is part of the skill.
This is why every question here carries a written explanation rather than a letter: the explanation is what converts a wrong answer into learning, and a bare key gives you nothing to retrieve next time.
What is the single highest-return habit?
Keeping a written list of what you got wrong, one line each, with the reason. It takes a few seconds per question and almost nobody does it.
The value is that after two weeks the list is a map of your actual syllabus rather than the official one. Every student has a personal set of about forty recurring weaknesses, and they are worth more of your attention than the nine hundred things you already know. Without the list you cannot see them, because the memory of each individual mistake fades within days.
Write the chapter and the reason, not the question
"Enzyme inhibitors: confused competitive and non-competitive." That is retrievable. Copying the whole question out is slow and you will not reread it.
Review the list weekly, not daily
Ten minutes. Read each line and try to answer it from memory before checking.
Cross a line off only after getting it right at a gap
Right once, a week later, without looking. Anything less and it goes back on the list.