I built my own curriculum. Here's what school was actually for.

I do Pearson Edexcel International A-Levels in Economics, Mathematics and Business, and I built the curriculum myself.

That sentence gets one of two reactions. Either it sounds like an excuse — the kid who could not hack a real school — or it sounds like a flex, the autodidact who transcended the system. It is neither, and the gap between what I expected and what actually happened is the only part worth writing down.

#What I expected to be hard

Content. I assumed the difficulty of teaching yourself three A-Levels was the material: no teacher to explain the Keynesian multiplier, nobody to check whether I had understood integration by parts.

The content was the easy part. That says nothing about me and everything about how much good material now exists. The Edexcel specification is a public document that tells you, in order, every single thing you will be assessed on. Past papers go back years. Mark schemes explain not just the answer but what the examiner is looking for in the wording.

The syllabus is not a secret. It has never been a secret. School's advantage was never that it knew what was on the exam.

#What was actually hard

Knowing whether I was right.

In a classroom you produce work and something happens to it. It comes back with red on it. The red is often not very good — a tick, a mark, three words — but it is external, and external is the whole point.

Alone, you write an essay on price elasticity, read it, and think it is fine. It is fine. That is the problem. You have no way of knowing whether it is a grade-A answer or a competent grade-C one, because the difference is invisible from inside your own head. You wrote the thing using the understanding you have. Of course it looks complete to you.

I spent three months getting steadily better at writing essays I thought were excellent and had no evidence about. The feedback loop was not slow. It was absent.

This is, directly, why I built Veridian. Not as a business idea — I did not have one. I had a problem, which was that I needed something to mark my work with the specificity a good teacher would, and there was nothing that did it. Four million words of knowledge base later there was, and it marked full papers with grade, UMS, and assessment-objective breakdowns, and it flagged which of its own judgements it was unsure about.

Then it got me an A* and 98%, and then two schools and seventy students bought it, and the thing I built to solve my own feedback problem became a company. That order matters. The company was downstream of the problem, not the other way round.

#The second hard thing

Nobody sets the pace.

School's real product is a calendar with other people on it. Information was always the side effect. You do the reading because there is a lesson on Tuesday and a person will ask you about it. You revise because the mocks are in three weeks and everyone around you is revising.

Take that away and you are left with pure self-direction, which sounds like freedom and functions, initially, like a slow leak. Nothing is due tomorrow. Nothing is ever due tomorrow, right up until everything is.

What fixed it was not motivation. It was building a fake version of the thing I had removed: a fixed weekly schedule, blocks at the same times, a real paper under timed conditions every fortnight whether or not I felt ready. The timed paper is the load-bearing part. It is the only thing in the week I cannot negotiate with, and it is the only thing that reliably tells me where I actually am.

#What I got that school could not give me

The pace, in the other direction.

The single largest gain from homeschooling is not learning better. It is not spending forty minutes on something I understood in six. A classroom moves at the speed of the median student, and it must, and that is not a criticism of teachers — it is arithmetic. If you are ahead on a topic you wait. If you are behind you drown quietly.

Alone, I spent about three weeks total on the parts of the maths spec I already had, and something close to two months on the two topics I kept getting wrong. No system with thirty students in a room can allocate time like that.

The second gain is that the day is mine. I run an agency, I mentor twelve founders, I have clients on three continents. Those are not extracurriculars I fit around a timetable. They are why the timetable had to be mine.

#The honest ledger

Things I lost, which I do not think people mention:

• Being told I was wrong by someone who did not have to be gentle about it. I had to build that in artificially, and it is not the same.
• The friction of other people's questions. Half of what I understood in a classroom, I understood because someone else asked something I had not thought to ask.
• A default. On a bad week, school happens to you anyway. Homeschooling does not happen to you.

Things I would say to someone considering it: the material is available and free, the exams are gettable, and the specification will tell you exactly what to do. None of that is the question.

The question is whether you can build, from nothing, the two things a school was quietly supplying while you thought it was supplying facts — a way of finding out you are wrong, and a reason that tomorrow is not next week.

If you can, the rest is just reading.