Slippage memory
Posted: Fri Oct 30, 2026 10:41 am
Slippage memory
One ugly fill can change the way a trader behaves for days. A stop slips four pips on a news spike. From then on, entries are hesitant, stops are placed wider than the plan, and the size drops.
The hesitation is understandable. It also creates a distorted version of the strategy, one that the original testing never covered. Wider stops with smaller size are not the same system.
The flinch tends to fade after a few weeks, but by then the damage to the results has been done. A strategy that works on its original parameters may seem broken, and the trader starts changing it.
A cleaner approach is to separate cause from effect. Was the slippage a one-off, caused by an event that the strategy should avoid? If so, add a filter and move on. If it reflects a persistent cost, adjust the model and retest.
Letting a single event rewrite the rules is a recipe for inconsistency.
Has a single bad fill ever led to a change in strategy that turned out to be unnecessary?
One ugly fill can change the way a trader behaves for days. A stop slips four pips on a news spike. From then on, entries are hesitant, stops are placed wider than the plan, and the size drops.
The hesitation is understandable. It also creates a distorted version of the strategy, one that the original testing never covered. Wider stops with smaller size are not the same system.
The flinch tends to fade after a few weeks, but by then the damage to the results has been done. A strategy that works on its original parameters may seem broken, and the trader starts changing it.
A cleaner approach is to separate cause from effect. Was the slippage a one-off, caused by an event that the strategy should avoid? If so, add a filter and move on. If it reflects a persistent cost, adjust the model and retest.
Letting a single event rewrite the rules is a recipe for inconsistency.
Has a single bad fill ever led to a change in strategy that turned out to be unnecessary?