Your mistakes are worth more than your correct answers

Think about what happens when you get a question right. You already knew it. You learn nothing. It feels good, which is why students gravitate towards practising the topics they are already strong at — that is the pleasant part of studying.

Now think about what happens when you get one wrong. You have just been handed a precise, specific instruction about where your preparation is thin. That is genuinely valuable information, and most students throw it away within about four seconds of receiving it.

What most people do with a wrong answer

They look at the correct option, think "oh, of course", and move on.

The problem with "oh, of course" is that it feels like understanding but is actually recognition. When you see the right answer, your brain fills in a story about why it is right and you walk away convinced you now know it. Three weeks later, in the exam, the same question appears and the same mistake comes out.

What to do instead

Keep every mistake, and revisit it when you have forgotten the answer.

Concretely, that means writing down three things for each one:

1. The question, in full. Not "Q7 chapter 3" — the actual question, because in a month "Q7" will mean nothing.
2. What you answered, and why you thought so. This is the part everyone skips and the part that matters most. "I picked B because I thought momentum was conserved here" is a diagnosis. "Wrong answer" is not.
3. What is actually true, in your own words. Copying the explanation out of the book does not work; if you cannot say it in your own words you have not got it yet.

Then — and this is the whole point — come back to that list a week later and try the questions again, cold.

The pattern is the real prize

Once you have thirty or forty mistakes written down, stop and read the list as a whole. You will find that they are not scattered randomly. Almost everyone has two or three recurring failure modes, and yours might be:

• Consistently mixing up two similar formulas.
• Losing marks on units and significant figures rather than method.
• Misreading questions that contain "not" or "except".
• Rushing the last four questions because the first four took too long.

Each of those has a different fix, and none of them is "study harder". The third one is fixed by underlining the word "not" as you read. The fourth is a pacing problem, not a knowledge problem, and no amount of extra revision will touch it.

You cannot see any of this from inside a single test. It only appears when the mistakes are collected in one place.

Making it automatic

The honest problem with mistake notebooks is that keeping one by hand is tedious, and the students who need it most are the least likely to keep it up for a full term.

This is the one piece of the loop worth automating, which is why Parho fills the notebook for you: every question you get wrong is kept with its explanation, grouped by the paper you sat, until you mark it reviewed. You still have to do the thinking — writing down why you thought what you thought is not something software can do for you — but you never have to do the copying.

Whichever way you keep it, keep it. The questions you got right are not going to teach you anything new.