Here's an IB person showing book trader, just watching this you can imagine how quick this is in the right hands ...
https://www.tradingheroes.com/paul-rotter-the-legend-the-myth-the-man/ https://www.elitetrader.com/et/threads/pabst-questions-regarding-pit-trading.71503/ Hope this helps a bit to understand what scalping is about...
Scalping is trading style characterized by zero tolerance to opened profit declining. This means trading "retracement-less" movements. These movements can be on 5 sec chart and also on weekly chart. It's not about many trades per unit of time, it's about not holding during retracements, scalper exits while the price continues to move in his/her advantage (so called positive slippage).
This really isn't so at all. For their entry to be a valid/correct one, scalpers need the price to move (albeit not far) in "their direction" almost immediately, otherwise they don't want to be in the trade, and for this this reason, they typically use tiny stop-losses.
100% correct "immediately" is relative to the working timeframe, so "immediately" on 5min is not the same that on daily, etc
The reason the trades are high probability is because of the small profit target.... if you take a profit every time you show a small profit, you will have a high rate of success but small profits.... that is his scalping works...