Backtest
Running a rule on past data to see how it would have done. Easy to fool yourself with.
A definition says what a thing is; it never says whether it fits you. The guides explain how it works and name the professional who confirms it for a particular person. The No Advice Disclosure.
Ask about Backtest
A model reads this page and answers from it. It will say when the answer is not on the page. Education, not personalized advice.