How the markets are measured, and what the numbers turned out to mean.
Profit factor is gross profit divided by gross loss. Above one you made money. It is quoted everywhere and misread almost as often - here is what it measures, what it hides, and the number to read beside it.
Win rate, average R, profit factor, drawdown and trade count each answer one question and dodge another. The lower bound answers the question that matters - is this real - and it is the one most tools leave out.
A backtest is a replay of fixed rules over past prices. Done right it tells you whether an edge exists. Done the usual way it tells you what you wanted to hear. The difference is six decisions.
A strategy that shows +1.13R per trade over four trades is not a strategy, it is a coin that landed well. Here is the number we plan on instead, and why the engine refuses to run without it.