About Checked the Math
I design and run systematic, factor-based equity trading strategies — the kind that make decisions from data and backtested rules rather than opinion. I've spent years building these systems, and more time breaking them: running out-of-sample tests, chasing down results that turned out to be noise, and learning firsthand how easy it is to fool yourself with a backtest that looks great until you ask it the right question.
Checked the Math applies that same standard to the claims investors repeat to each other constantly, but that few people actually test. Does dollar-cost averaging really beat investing a lump sum? Does waiting for a dip pay off? Is the 4% rule still safe? I don't sell a strategy here, and I don't publish the parameters of the ones I trade — this site exists to test common wisdom against real market data, using code you can rerun yourself.
What "checked" means here
Every post on this site follows the same rules, because these are the ones I've watched people — including myself — get wrong:
- State the data and the window before the conclusion. A result that only holds in one time period isn't a result, it's a description of that period. When a longer or different window changes the answer, that goes in the post, not in a footnote.
- Report the case where the claim wins, if there is one. A rule that never wins under any condition is suspicious; so is one that wins under conditions nobody mentions. Both get reported.
- Publish the code. Every post links the script that produced its numbers. If you rerun it and get something different, I want to know — that's not a hypothetical, it's the actual review process for this site.
- Say what the result doesn't tell you. Every post ends with the limitations of the method used to reach it, stated plainly, not hedged into meaninglessness.
What this site is not
This is research, not personalized financial advice. Nothing here is a recommendation to buy, sell, or hold anything, and none of it accounts for your specific situation. I'm not a licensed financial advisor, and posts on this site shouldn't be read as a substitute for one. Where a post touches tax, legal, or regulatory specifics, I say so and point to where to verify it — those rules change, and change by jurisdiction.
Corrections
If a post turns out to be wrong — a data error, a bug in the code, a conclusion that doesn't hold up on closer look — I correct it and note the correction on the post itself with a date. I'd rather be told I'm wrong than be quietly wrong.
Contact
hello@checkedthemath.com — questions, corrections, or a claim you'd like tested.