Guardrails Against Illusions of Skill
Even elegant spreadsheets can promise ghosts of alpha. Protect validity through out-of-sample testing, walk-forward evaluation, and strict partitioning of training and validation windows. Avoid data snooping by documenting each parameter change with timestamps and rationale. Prefer robust, simple rules that survive perturbations. When results hinge on a fragile setting or tiny subset of assets, consider whether you have discovered opportunity or noise. Good process here prevents later regret when markets shift abruptly.