Position Sizing
Also called: bet sizing, risk per trade, Kelly criterion
Position sizing decides how much capital goes into a trade, and it matters more than entry selection. Risking 1–2% of capital per trade means a losing streak is survivable; risking 20% means two bad weeks ends the account. The Kelly criterion gives a mathematically optimal size given edge and odds, and practitioners generally trade a fraction of it because Kelly's own volatility is brutal.