Quote from sunmoon:
quote from blueberrycake (on another, but related thread "ES Scalping, is it worth?":
Think about it this way, it's extremely rare to buy the bid/sell the ask in ES without the price ticking through to the next level.
Hence in order to hit your target of .25, the price actually needs to move .5 in your direction. But to get stopped out at .75, the price only needs to tick down by .5.
So if are long, and the price moves up by .5 you make .25, but if it moves down by .5 (the exact same amount), you lose .75 or three times as much. In this setup you have to be right 75% of the time to break even before commissions.
----------------------------------------------------------
I have been backtesting a scalping system over all the ES historical data possible (7+ years+), and my annual return is well over 70% with max 15% drawdown.
Now, my only concern is the fill price. I base my entries and exits on closing 1 min prices. So if my data shows 1000.75 as the close price of minute 10:46, that's the price my simulated entry goes in. In other words, I don't take into account slippage, or anything that blueberrycake refers to in the quote above.
How realistic is slippage? Since my entry isn't based on trend-following indicators, shouldn't have a 50/50 (or even better than 50/50, since i'm going opposite to trend) chance of either upticking or downticking? In other words, if I don't get filled in at 1000.75, shouldn't there be a 50/50 chance of either 1000.50 or 1100.00? Any help would be appreciated, thanks in advance.