Scaling out can be a superior strategy though. Let's consider the following example:
In this hypothetical example we would consider 2 accounts both trading 2 contracts (ES), same entries, but different exits. The non-scale out account would be aiming to achieve +9 points with a -3 point stop full position in and out, whereas scale out account would scale out 1 contract after +3 point gain and hold 1 contract for +9 point gain or stop at entry, with an exit of 2 contracts at -3 point loss, just like the non-scale out account.
After 100 trades the non-scale out account generated 70 losing trades due to inability to generate a high percentage of +9 point winners as price would go up some, reverse failing to reach +9 and position would have been taken out at -3 point loss 70 times.
A) 2 x 70 losers at 3 points x $50 -21,000
B) 2 x 30 winners at 9 points x $50 +27,000
Gross non-scale out: +6,000
After 100 trades the scale out account generated more winners than non-scale out account due to scale out of 1 contract after +3 point gain was reached and then the same 30 trades generated +9 point gain (as in the non-scale out account) but with 1 contract.
This is a very realistic outcome based on intraday behaviour of price, it goes up some, then reverses taking out stops and then maybe going back in the previously correctly anticipated direction. The $ advantage is clearly in the scale out account, because the non-scale out account generated a lower win rate due to either going for -3 or +9 full position whereas a higher win rate was achieved in the scale out account as we locked at +3 half position.
C) 2 x 30 losers at 3 points x $50 -9,000
D) 1 x 70 winners at 3 points x $50 +6,000
E) 1 x 30 winners at 9 points x $50 +13,500
Gross scale out: +10,500
Open to debate