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Why win rate is the most misleading number in trading

  • A win rate tells you how often you win. It tells you nothing about how much.
  • Those are the two halves of the answer, and it only reports one of them.

What it is, and what it leaves out

  • Win rate is the share of trades that finished in profit. That is all it is.
  • It says nothing about the size of the wins.
  • It says nothing about the size of the losses.
  • And the losses are where the money goes, on every strategy that sells premium.

The clearest case

Take the same $5-wide spread, but sell it further out for a smaller credit — $25 instead of $93. The maximum loss is now $475.

  • The breakeven win rate is 95%. That is $475 of risk over a $500 width.
  • Win 95% of the time and you have made nothing.
  • Win 94% and you are losing money, while nineteen trades in twenty come out green.
  • A trader in that position sees an almost perfect record and a shrinking account, and has no idea which number to distrust.

Arithmetic from the stated specification — a $5-wide spread taken for $25. The win rates are assumed to make the point, not measured.

Why it is so persuasive anyway

A high win rate is not evidence of skill. It is a description of where you put the strikes.

  • Sell far enough from the money and a high win rate is guaranteed — by construction, not by insight.
  • It arrives before the losses do. The wins are frequent and small; the losses are rare and large, so a short record looks superb.
  • It feels like being right. Nineteen green trades in a row is a powerful experience and it is not information.
  • And it is the easiest number to publish, which is why it is the one you see.

The mirror image

  • A debit spread strategy can be sound at a 35% win rate.
  • It loses often and small, and wins rarely and large.
  • So comparing a credit strategy and a debit strategy on win rate is meaningless — they are built to have different ones.
  • It is done constantly.

What to ask instead

  • What is the expectancy per trade? That is the answer — see expectancy.
  • What is the breakeven win rate for this structure? Compare the actual one against it, not against 100%.
  • What is the worst single trade? On a high win rate strategy that number is the strategy.
  • How many trades is this from? A 90% win rate over thirty trades means the three losses you have seen are the entire sample of the thing that matters.

Why we publish it at all

  • Because leaving it out would look evasive, and because readers want it.
  • It is printed next to the expectancy and the breakeven win rate, so the three can be read together.
  • On its own it is the most misleading number in trading. Beside the other two it is genuinely useful.

Common questions

Can a 95% win rate lose money?

Yes, and it does not take anything unusual. A $5-wide spread taken for $25 has a breakeven win rate of exactly 95% — so 95% is break even and anything below it is a loss.

Is a low win rate a bad sign?

Not on its own, any more than a high one is a good sign. A strategy that wins a third of the time and wins big can be excellent.

Why do brokers and platforms show win rate so prominently?

It is simple to calculate, easy to understand, and it makes trading records look better than they are. Expectancy needs the sizes as well, and it flatters nobody.

What win rate should I aim for?

None. Aim for positive expectancy after costs; the win rate is whatever the structure produces on the way.

How this shows up in our tests

Every test on this site prints its win rate, and no verdict is decided by it.

The verdict comes from expectancy. When the first result publishes, both numbers will be there together, along with the breakeven win rate the structure needed in the first place.

The number

What is
expectancy?

The centre

What is a
specification?

The method

What is a
backtest?