You can win most of your trades and still go broke. You can lose most of them and get rich. Both facts confuse people because both break the intuition that trading is about being right. It is not. Trading is about expectancy, which is the average amount you make or lose per trade once you account for how often you win and how much you win and lose when you do. It is one number, and it is the only one that tells you whether you have a business or a hobby that occasionally pays.
Almost every other metric traders obsess over is a fragment of expectancy viewed on its own. Win rate is a fragment. Average win is a fragment. Profit factor is expectancy wearing a different outfit. Once you understand the one number, the fragments stop being able to fool you.
The number itself
Expectancy is your average result per trade. The simplest honest way to state it: take every trade's result in R, where R is the amount you risked on that trade, add them all up, and divide by the number of trades. That average, in R per trade, is your expectancy. A trader with an expectancy of +0.2R makes, on average, a fifth of their risk per trade. Over hundreds of trades that compounds into a real edge. An expectancy of zero is a coin flip that pays your broker. A negative expectancy is a slow leak with extra steps.
You can also write it as win rate times average win minus loss rate times average loss. Same number, more moving parts. The reason the R version is cleaner is that it stops you kidding yourself. A 3R winner is a 3R winner whether the trade was in gold or a currency cross, because R normalises for size and instrument. If you have never worked in R, the case for it over raw currency and over win rate is made in R-multiple versus win rate , and it is worth internalising before you go further.
Why win rate on its own is a trap
Here is the scenario that breaks most beginners. Two traders, same market, same year. Trader A wins 70% of the time. Trader B wins 35% of the time. Who is doing better? You cannot possibly say, and anyone who answers is guessing.
Suppose Trader A's winners average +0.4R and their losers average one full R. Their expectancy is 0.7 times 0.4 minus 0.3 times 1, which comes to minus 0.02R. A 70% win rate that loses money, slowly. Now Trader B, at 35%, with winners averaging +3R and losers one R. That is 0.35 times 3 minus 0.65 times 1, which comes to plus 0.4R. The trader who is wrong two times out of three is running twenty times the edge of the trader who is right seven times out of ten.
This is not a contrived example. It is the single most common way retail traders bleed out: a high win rate built on small winners and the occasional large loser, which feels wonderful and slowly empties the account. Your win rate makes you feel skilful. Your expectancy tells you the truth.
Why it ties everything together
Expectancy is the number that every other decision in trading feeds into, which is why it deserves to sit at the centre of your journal.
Your setups are worth keeping or cutting based on their individual expectancy, not their win rate or how much you enjoy them, which is the whole exercise of finding your edge from your journal . Your position sizing only makes sense once expectancy is positive, because size multiplies whatever edge you have, including a negative one. Sizing up a losing strategy just loses faster. Your behaviour leaks , the revenge trades and the boredom trades, show up as subsets that drag your overall expectancy below what your good trades would produce alone. Your improvement over time is legible as expectancy trending up across a growing sample. One number, and it audits everything upstream of it.
Expectancy per trade versus expectancy per unit of time
A subtlety worth getting right, because it changes decisions. Expectancy per trade tells you the quality of your average trade. But two strategies with the same per-trade expectancy are not equally good if one produces four times as many valid trades. A +0.3R strategy that fires ten times a week beats a +0.5R strategy that fires once a month, in total return, by a wide margin.
This cuts both ways, and it is where traders err in opposite directions. Chasing frequency tempts you into low-quality trades that drag your per-trade number down, which is the mechanics of overtrading. Chasing per-trade quality tempts you into sitting on your hands and undertrading a genuine edge. The right target is total expectancy, per trade multiplied by frequency, weighed against the drawdown you have to stomach to get it. You cannot manage that trade-off without both numbers logged.
What expectancy does not tell you
Expectancy decides whether you make money, but it is not the whole risk picture, and pretending it is will hurt you. Two strategies with the same positive expectancy can feel completely different to trade if one gets there through steady small edges and the other through rare enormous winners between long losing runs. The average is identical. The drawdown you have to sit through, and the odds you quit before the winners arrive, are not.
So track expectancy as your headline number, but keep the shape of the distribution next to it. Look at your worst losing streak, your largest single loss, and how lumpy the R results are. A positive expectancy you cannot psychologically survive is a positive expectancy you will abandon at the worst possible moment, which turns a winning strategy into a losing trader. The number tells you the edge exists. The distribution tells you whether you can actually hold on long enough to collect it.
How to track it so it means something
Three things make an expectancy number trustworthy. First, a large enough sample: expectancy over twenty trades is a rumour, over two hundred it starts to be evidence. Second, results recorded in R, so size differences do not distort the average. Third, the ability to compute it on any subset, because your overall expectancy is far less useful than the expectancy of your London trades, or your A-setups, or your trades taken when you followed your plan. A journal where the fields you track become statistics you can filter on, as they do in TradeSave+, means you can pull expectancy for any slice on demand instead of exporting to a spreadsheet every time you have a question.
Then the discipline is boring and non-negotiable: check it on a rolling basis, on a sample big enough to trust, and let it, not your win rate and not your best week, be the number you judge yourself on. If you want the machinery for turning that number into a strategy you can actually follow, that is the job of a trading plan . Expectancy tells you whether the plan is any good. The plan is how you keep producing the trades that generate it.