Target Distance Moves Win Rate Mechanically
Take a breakout rule, keep every condition that decides whether to enter exactly as it is, and shorten the target. The win rate will rise. Lengthen it and the win rate will fall. Nothing about the range, the trigger definition or the judgement involved has been touched. The number moved because a parameter moved, which is worth sitting with, because it means the win rate is partly something you set rather than something you discover.
The Mechanism Is Not Subtle
Price, once a position is open, is going to travel some distance in your favour before it either reverses or reaches wherever you decided to exit. A target placed close to the entry is inside almost every favourable excursion. A target placed far away is inside only the excursions that were large.
Since large moves are rarer than small ones, moving the target out reduces the proportion of trades that reach it. That is arithmetic about the shape of price movement rather than a claim about any strategy, and it holds regardless of how good the entry rule is.
The same logic applies to the stop in the opposite direction. A stop placed further away is reached less often, so the win rate rises. Every change to either exit moves the count, and the count moves before anything about the quality of the decision has changed.
What Gets Paid for the Improvement
The trade is exact and easy to state. A nearer target converts trades that would have been large winners into small ones. The count improves and the size of the average win falls, because the moves that would have carried furthest were capped along with everything else.
A wider stop converts trades that would have been small losses into larger ones. Again the count improves, and the size of the average loss grows. In both cases the money is being moved from one column into another while the reported percentage looks better. The easiest route to an impressive number is therefore the change that damages the system, and nothing in the number itself reveals it.
Fixed Targets and Adaptive Targets Behave Differently
A target expressed as a fixed distance produces a win rate that drifts with conditions. In a quiet stretch that distance is far and the rule wins rarely. In a volatile stretch the same distance is close and the rule wins often. The parameter did not change, the market did, and the count moved anyway.
A target expressed relative to something that scales, such as the height of the range or recent typical movement, produces a steadier win rate across conditions because it is asking for a comparable amount of movement each time. That stability is worth something on its own, since it means a change in the number is more likely to carry information rather than reflect the weather.
Neither approach is automatically right, but the difference should be understood before comparing win rates measured under one with win rates measured under the other.
Where the Range Itself Comes In
An opening range breakout has a complication that many strategies do not. The range that generates the signal also consumes part of the day's available movement before the trade is even taken. A tall range leaves less distance for the position to travel, so a fixed target sits proportionally further away in terms of what remains.
The result is that the same target distance is a different demand on a wide range day than on a narrow one, and a win rate averaged over a mixture of both is averaging two different things. Splitting the record by range height often shows the count varying considerably between them, which is more useful than the single figure that combines them.
How to Use the Number Once You Know This
The first consequence is that a win rate should never be quoted without the exit rules attached. The pair of numbers describing where the target and the stop sat is not supplementary detail. It is the context that makes the percentage mean anything at all.
The second is that changes in win rate are only informative when the exits held still. If the target has been adjusted, the count is expected to move and its movement says nothing. If nothing was adjusted and the count moved anyway, that is a real observation about conditions or about the entry rule, and it is worth investigating.
The third is a caution about tuning. It is possible to search through target and stop distances until the win rate looks good, and the search will always succeed, because the relationship is mechanical. A number arrived at that way describes the search rather than the strategy, and it will not survive contact with a period the search never saw.