Clustered trades are one bet, not five
Posted: Sat Oct 31, 2026 7:32 pm
Clustered trades are one bet, not five
A scalper takes five trades in ten minutes, all long EURUSD, each from a slightly different level. The journal shows five trades. The market sees one bet.
The outcomes are highly correlated. If the direction is wrong, all five lose. If right, all five win. The effective sample size is closer to one than five.
This matters for statistics. A win rate of 60 percent over 100 trades might consist of 20 independent decisions with five trades each. The confidence interval is much wider than it appears.
It matters for risk too. Five clustered trades carry five times the exposure of one, concentrated on a single idea.
Grouping trades by time window or by signal, and counting each group as one observation, gives a more honest picture. The number of independent bets in a month is often small.
For evaluation, using group-level results shows whether the strategy truly has an edge or whether a few lucky clusters drive the results.
Sizing accordingly means treating a cluster as a single position and judging its total risk, not each leg separately.
A practical fix is to define a cooldown: after a trade is opened on a given pair and direction, no new trades in that direction on that pair for a set number of minutes unless the first has closed. That naturally limits clustering and forces each new trade to be a separate decision.
Another is to report all statistics at the cluster level. Win rate per cluster, average profit per cluster, and the standard deviation across clusters give a much more honest basis for judging whether a strategy is working. The numbers are usually less impressive and far more useful.
Group clustered trades together and count again: how many independent decisions are in the last month?
A scalper takes five trades in ten minutes, all long EURUSD, each from a slightly different level. The journal shows five trades. The market sees one bet.
The outcomes are highly correlated. If the direction is wrong, all five lose. If right, all five win. The effective sample size is closer to one than five.
This matters for statistics. A win rate of 60 percent over 100 trades might consist of 20 independent decisions with five trades each. The confidence interval is much wider than it appears.
It matters for risk too. Five clustered trades carry five times the exposure of one, concentrated on a single idea.
Grouping trades by time window or by signal, and counting each group as one observation, gives a more honest picture. The number of independent bets in a month is often small.
For evaluation, using group-level results shows whether the strategy truly has an edge or whether a few lucky clusters drive the results.
Sizing accordingly means treating a cluster as a single position and judging its total risk, not each leg separately.
A practical fix is to define a cooldown: after a trade is opened on a given pair and direction, no new trades in that direction on that pair for a set number of minutes unless the first has closed. That naturally limits clustering and forces each new trade to be a separate decision.
Another is to report all statistics at the cluster level. Win rate per cluster, average profit per cluster, and the standard deviation across clusters give a much more honest basis for judging whether a strategy is working. The numbers are usually less impressive and far more useful.
Group clustered trades together and count again: how many independent decisions are in the last month?