Reference
The terms used across this site, defined once and precisely enough to argue with.
Every term this site uses, defined once. 54 entries across 5 groups, each with the formula where one exists and the misunderstanding worth heading off. Where a page or calculator goes further, the entry links to it.
How many units, lots, shares or contracts to trade so that the distance to your stop costs exactly the amount you decided to risk. It is an output of the other three numbers, never an input.
The share of the account a single loss costs, fixed before the trade. Between 0.5% and 2% is conventional, and the reason is the drawdown arithmetic rather than caution for its own sake.
One unit of the risk taken on a trade. A trade that made twice what it risked returned +2R; one stopped out returned −1R. Expressing results in R makes them comparable across position sizes and accounts.
The result of a trade divided by the amount risked on it. The figure to record in a journal, because unlike a dollar result it does not change meaning when the account size does.
The price at which the trade idea is wrong, decided before entry. It sets the position size; it is not a lever for making a position bigger.
A stop moved to fit a position size you already chose is not a stop — it is a hope with a price attached.
Reward divided by risk, measured to the target and the stop. Meaningless in isolation: what it fixes is the win rate the trade needs to break even.
The frequency at which a given payoff ratio makes exactly nothing. 1:1 needs 50%, 1:2 needs 33.3%, 1:3 needs 25% — all before costs, which raise every figure.
Risking a constant percentage of the current account rather than a constant dollar amount. Position sizes shrink after losses and grow after gains, which is what makes outright ruin arithmetically hard.
The fraction of capital that maximises long-run growth for a given edge and payoff. Almost nobody should trade it in full: it assumes the inputs are known exactly and produces drawdowns above 50% routinely.
The probability an account falls to a chosen floor before it grows. Position size dominates the result far more than the edge does — the same strategy at 2% and at 10% risk differs by orders of magnitude.
Every assumption in the standard formula fails in the same direction, so the figure it produces is a floor, not an estimate.
The average result of one trade taken over many, combining how often you win with how much you win when you do. The only single number that says whether a strategy earns anything.
The share of trades that closed profitable. On its own it says nothing about whether a strategy earns: a 70% win rate with large losers loses money, and a 40% win rate with large winners does not.
A win rate from under a hundred trades cannot separate a good strategy from a poor one — the interval is roughly ±10 points at n=100.
The fall from a peak in account equity to the lowest point before a new peak. Measured as a percentage of the peak, not of the starting balance.
The deepest peak-to-trough fall in a record. An extreme-value statistic from a finite sample, so it systematically understates what is possible — plan for worse than you have seen.
Gross profit divided by gross loss. Above 1.0 is profitable, but the figure says nothing about the sample size that produced it.
Sharpe with downside deviation in the denominator instead of total volatility. Usually the higher of the two, because it stops treating good surprises as risk.
Annualised return divided by maximum drawdown. A crude but useful way to compare strategies on the axis that decides whether one is holdable.
Account value plotted over time. Its shape carries information the total return does not: the same final figure reached smoothly and reached through a 50% hole are different strategies.
The fourth decimal place on most currency pairs and the second on JPY-quoted ones. On a standard lot of a USD-quoted pair it is worth $10; on a JPY-quoted pair its value depends on the current rate.
A tenth of a pip — the fifth decimal place on most pairs. Brokers quote them for finer pricing; the value is a tenth of the pip value.
A standard unit of position size in forex. A standard lot is 100,000 units of the base currency, a mini lot 10,000, a micro lot 1,000.
The gap between the bid and the ask, paid on entry. Judge it as a share of your stop distance rather than in isolation: 1 pip against a 10-pip stop is a tenth of the trade.
A per-lot charge, usually levied on both sides, so a quoted rate is half the round-turn cost. A raw-spread account with commission and a zero-commission account with a wider spread often cost the same.
The financing charge or credit for holding a position overnight, from the interest-rate differential plus the broker's markup. Most brokers charge three days of it on Wednesday to cover the weekend.
The difference between the price you expected and the price you were filled at. It widens in fast markets and at gaps, which is why a stop is a floor on the loss rather than a guarantee.
Total position notional divided by account equity. The number that matters is the leverage you are using, not the maximum the broker permits.
The deposit a broker holds against an open position. It is not risk: a position can sit well inside your margin and far outside your risk budget.
Confusing margin with risk is the most common way an account becomes over-leveraged without anyone noticing.
The point at which a broker closes positions because equity has fallen below a maintenance level, commonly 50% of margin. Sizing by risk rather than by margin keeps you well clear of it.
The full face value of a position — units times price — as opposed to the margin posted against it.
The periodic payment between long and short holders of a perpetual futures contract, charged every few hours. The crypto equivalent of swap, and the dominant cost on a leveraged position held for weeks.
Open, high, low and close — the four prices that define a bar. Every formation rule on this site is a condition over these four numbers and nothing else.
A bar drawn so the body spans the open and close and the wicks reach the high and low. The colour convention tells you which of open and close is higher; the shape carries the rest.
The distance between a bar's open and close. Most candlestick rules are statements about the body as a share of the bar's full range.
The line above or below a candle body, reaching to the high or low. Also called a shadow or a tail. A long wick means price went there and did not stay.
The largest of the bar range, the distance from the high to the previous close, and the distance from the low to the previous close. Unlike the bar range it counts overnight gaps.
Average True Range — the mean true range over N bars, conventionally 14. Used to size stops in units of what the instrument is currently doing, so one rule means the same on gold and on EURUSD.
Average Daily Range — the mean of recent daily ranges. Describes where the average day ends, not where today will: half of all days exceed it by definition.
The standard deviation of returns, usually annualised by multiplying by the square root of the periods in a year. The scaling assumes returns are independent, which real series are not.
A discontinuity between one bar's close and the next bar's open, so no trading occurred at the prices in between. Also called a window in candlestick terminology.
A local high or low that dominates the bars either side of it. Its position is not known when it forms — only once enough further bars have printed without exceeding it, which is why chart-formation detections lag the shape.
The period each bar covers. Shorter timeframes produce more signals, more noise, and proportionally larger costs, because the spread is paid per trade while the move shrinks.
Running a rule over historical data to see what it would have done. It tells you what would have worked on one sample under assumptions you chose — not what will work.
A rule using information that was not available when it fired. The most common form is reading the still-forming bar, whose close does not yet exist.
This is not hypothetical here: a completed study on this site was withdrawn for exactly it.
Testing only the instruments that still exist. What is missing is missing precisely because it went badly, so the result is measured on the winners.
Choosing parameters by trying many and keeping the best. The result then describes the sample rather than the market, and it does not survive out of sample.
Running many tests and reporting the ones that worked. At p<0.05, roughly 5 of every 100 rules look significant on noise alone, so a family of tests needs a correction across all of it.
A false-discovery-rate correction applied across a whole family of tests. Less conservative than Bonferroni and the appropriate choice when testing a hundred-plus rules at once.
Data held back and never looked at during development, tested once at the end. Testing it twice and adjusting in between converts it into in-sample data and destroys the only unbiased estimate you had.
Fitting on one window, trading the next, then rolling forward and repeating. It tests whether a strategy survives being re-fitted the way you would actually have to re-fit it.
What the same data did without the rule — typically an arbitrary entry on the same bars. The comparison is the finding: a 58% hit rate means nothing until you know an arbitrary entry scored 51%.
The range a measurement supports, given its sample size. It turns "it works" into "here is what the evidence actually permits", and it is the half most published pattern statistics omit.
Removing detections that share forward windows before computing a sample size. Clustered detections are not independent observations, and treating them as such narrows the interval and manufactures significance.
The minimum number of occurrences below which no rate is published. Reporting a percentage from a handful of events is noise with a decimal point attached.
Formation names are defined separately: 107 candlestick formations and 20 chart formations, each with the thresholds its detector uses. The whole reference is also available as plain text in one request.