It's 30 years, almost to the day, that I darkened Corpus's doors to study PPE - "a soft option for the weaker man". Which raises the question: what did I learn so long ago that's still useful?

I didn't learn much about how to interpret economic data; econometrics came in my masters degree, and I learnt the minutiae of official numbers on the job: I gather that this is still the case, which is a shame because you can go a long way simply by knowing what the heck the ONS are playing at.

Nor did I learn anything about Austrian economics. I don't remember Hayek's name even being mentioned (though I'd read The Constitution of Liberty at school).

Here then, is what I did learn:

1. Economics is the study of mechanisms, not models. The question is: through what mechanism does X affect Y? This'll change with time and place. The task, therefore, is not (merely) to solve models, but to ask: which one is most relevant to our current situation?

2. Economic theory has a history, which can be usefully studied. There are some problems which modern economics hasn't solved but ignored.

3. Economics cannot be studied in isolation. Any serious thought about economics will soon run into political questions such as the nature of power, or philosophical and psychological ones such as the nature of rationality.

4. Don't bore your reader. "Stir me up with a good first sentence", Brian Harrison told his students. One virtue of the tutorial system is that your tutor will let you know if his attention is flagging. This means you don't have to write all you know; brevity is a virtue (I'm looking at you Frances and Bill).

5. Read the original. If you want to know what, say, David Ricardo thought, read David Ricardo, not the secondary literature - even if it'll hurt like hell. This means not relying on media accounts of speeches or data.

6. Intelligence isn't everything. Amongst my rough contemporaries, the most conventionally successful have not been the smartest (in the narrow sense of the word), but the nicest - though I'll grant this mightn't be a representative sample. And if you want a first, the self-discipline required to knuckle down and revise matters more than raw IQ.

All this said, the biggest thing Oxford gave me was a love of Leonard Cohen and Hank Williams. At this distance, the biggest impact of university is perhaps psychological, not intellectual. Readers should be grateful I stop here.