Every model here started the same way: a question that kept coming up in post-mortems, that I couldn't settle by thinking harder about it. Is this a pattern or a story? Does the thing I believe about this market actually show up in the data, or have I been rewarded for it by coincidence?
The useful output is rarely a signal. More often it's a correction to an intuition — finding out that an effect I was confident about was mostly sector composition, or that a screen I trusted stopped working in exactly the conditions where I most needed it.
A note on detail. What follows is deliberately calibrated: enough to show the work was genuinely specified, built, and run, and not enough to reconstruct anything proprietary. Where a model was developed in a professional capacity, the description is confined to method and general findings — no employer attribution, no live results, no production parameters.