What is System Quality Number (SQN)?
System Quality Number combines average R-multiple expectancy with the square root of trade count to score how strong and how evidenced a system is.
Formula
SQN = (Mean R-multiple ÷ StdDev of R-multiples) × √(number of trades)
Indian market context (NSE)
Reference levels: Nifty 50 at 24,300, Reliance Industries at ₹1,300, Bank Nifty futures at 55,000 (lot size 30). Examples below show how System Quality Number (SQN) shows up on Indian index, equity, and futures books — update to live quotes in your journal.
Nifty 50 perspective
Apply System Quality Number (SQN) to your Nifty 50 sleeve (spot near 24,300): track the metric on closed index F&O or ETF trades over at least 30 sessions before changing rules. NSE costs and slippage on fast opens often widen the gap between spreadsheet system quality number (sqn) and bank P&L.
Reliance Industries perspective
On Reliance (₹1,300) delivery or intraday trades, calculate system quality number (sqn) with contract-note costs included. Single-name results can look strong on system quality number (sqn) while your Nifty-correlated book tells the opposite — tag “RELIANCE” separately in TradeLyser.
Bank Nifty futures perspective
Bank Nifty futures near 55,000 (lot 30) amplify system quality number (sqn) swings versus cash — one volatile session can move the metric more than a week of Nifty trades. Log margin mode (MIS/NRML) with each entry for honest review.
| SQN band (rule of thumb) | Interpretation |
|---|---|
| < 1.6 | Difficult to trade live with confidence |
| 1.6 – 2.5 | Average — improve or specialise |
| 2.5 – 3.5 | Good — still verify out-of-sample |
| > 3.5 | Strong — confirm sample size |
How to validate
- Minimum sample: 30 closed trades on one strategy tag before trusting System Quality Number (SQN).
- Check for one outlier week inflating System Quality Number (SQN) — export largest winners and losers.
- Recompute System Quality Number (SQN) after including brokerage, STT, and slippage on F&O tags.
- Compare System Quality Number (SQN) on the same date range as profit factor and max drawdown.
How to track in TradeLyser
- Open Strategy Board or analytics → filter by strategy tag and review period.
- Locate the widget or column reporting System Quality Number (SQN) (or export trades to compute manually).
- Store snapshot values in weekly review: System Quality Number (SQN), profit factor, drawdown, trade count.
- If System Quality Number (SQN) is custom, add a spreadsheet column fed from TradeLyser CSV export.
Best practices
- Publish System Quality Number (SQN) per strategy, not only at account level.
- Use the same calculation window (weekly vs monthly) year-round.
- Pair System Quality Number (SQN) with sample size in every review slide or note.
- Document formula used so mentors interpret the same number.
Common pitfalls
- Changing rules after fewer than 20 trades because System Quality Number (SQN) moved slightly.
- Mixing intraday and positional tags when computing System Quality Number (SQN).
- Ignoring costs so System Quality Number (SQN) looks better than banked P&L.
- Letting one outlier trade dominate the System Quality Number (SQN) reading.
How to use this in TradeLyser
Compute SQN only on closed trades with logged R-multiples. Split by instrument (Nifty vs stock F&O) before comparing scores.
Related terms
Expectancy answers whether your edge pays each time you repeat the setup. Positive expectancy means the system earns over many trades; negative expectancy means it bleeds even with a high win rate.
Profit factor summarises whether total winning rupees outweigh total losing rupees over a window. Below 1.0 means net losing; above 1.0 means net winning before you judge consistency.
Win rate is the share of your closed trades that closed in profit after costs. It tells you how often you are right — not how much you make when you are wrong.
FAQ
What is a good System Quality Number (SQN)?
A SQN of 2.0–2.4 is considered average, 2.5–2.9 is good, and 3.0–5.0 is excellent according to Van Tharp's benchmark scale. Scores above 5.0 are labeled superb but often indicate overfitting, especially on samples under 100 trades.
How do you calculate SQN?
SQN = (Mean R-multiple ÷ Standard Deviation of R-multiples) × √(number of trades). First convert each trade's outcome to an R-multiple by dividing P&L by initial risk, then compute the mean and standard deviation of those values, and multiply by the square root of trade count.
How many trades do you need for SQN to be reliable?
SQN is considered statistically meaningful at 30 or more trades. Below 25 trades the score is largely noise — a short lucky streak can produce an artificially high SQN that disappears as more trades are added.
What is the difference between SQN and profit factor?
Profit factor divides gross wins by gross losses in dollar terms, which makes it sensitive to position sizing and one large outlier trade. SQN uses R-multiples to normalize for risk, and it penalizes high variance — so two systems with the same profit factor can have very different SQN scores.
Can SQN be used for discretionary trading systems?
Yes. SQN applies to any set of trades where initial risk is defined before entry. Discretionary traders who set a hard stop loss on every trade can log R-multiples and compute SQN the same way a systematic trader would.
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