Field notes · trading & backtesting

The realbacktesting blog

Plain-spoken pieces on backtesting, prop-firm funding and how systematic trading actually works — written to be useful, not to sell.

Backtesting
Sortino ratio for prop backtests: what it misses

The Sortino ratio isolates downside deviation, but target choice, return frequency, and loss sequencing can still flatter a prop backtest.

5 min read
Backtesting
Confidence intervals for trading expectancy

A confidence interval shows how uncertain a backtest expectancy really is, and whether a positive average is doing more work than the evidence.

6 min read
Backtesting
Autocorrelation in trading backtests

Autocorrelation shows when ordered returns are related, making trade counts, Sharpe ratios, and drawdown estimates easier to overstate.

6 min read
Backtesting
Deflated Sharpe ratio for backtest selection

The deflated Sharpe ratio tests whether a selected backtest still looks credible after trial count, sample length, skew, and fat tails.

5 min read
Backtesting
News filters in prop backtesting

News filters can reduce event risk, but a prop backtest must prove the filter improves survival after missed trades and costs.

6 min read
Backtesting
Market regime backtesting for prop traders

Market regime backtesting checks whether a prop strategy survives trends, ranges, volatility shocks, and quiet tape.

7 min read
Backtesting
Time-to-target in prop backtesting

Time-to-target shows whether a prop backtest reaches a rule target before drawdown, costs, and variance break the account.

7 min read
Backtesting
Parameter sensitivity in prop backtesting

Parameter sensitivity shows whether a backtest survives small setting changes. Prop traders need a plateau, not one perfect setting.

6 min read
Backtesting
Exposure in prop backtesting

Exposure shows how much time and capital a strategy keeps at risk. In prop backtesting, the quiet hours can fail the account.

7 min read
Backtesting
Time-of-day filters in prop backtesting

Time-of-day filters change volatility, spread, fills, and drawdown clustering. A prop backtest must prove the clock helps.

7 min read
Backtesting
Take-profit distance in prop backtesting

Take-profit distance changes win rate, payoff, holding time, and rule pressure. A prop backtest must prove the target is reachable.

6 min read
Backtesting
Stop-loss distance in prop backtesting

Stop-loss distance changes sizing, costs, MAE, and rule pressure. A prop backtest must prove the stop survives the account.

6 min read
Backtesting
Why cross-validation leaks in trading

Cross-validation can leak future information in trading. Purging and embargoing keep the test set genuinely unseen.

6 min read
Backtesting
Trade frequency in prop backtesting

Trade frequency changes costs, clustering, and drawdown pressure. A prop backtest must show whether the pace is survivable.

6 min read
Backtesting
Losing streaks in prop backtesting

Losing streaks expose whether a prop backtest survives normal clustering. A profitable edge can still hit the rule floor.

6 min read
Backtesting
Minimum lot size in prop backtesting

Minimum lot size can make a small prop account trade differently from the backtest. Check it before trusting risk or drawdown.

5 min read
Backtesting
Average trade duration in backtesting, explained

Average trade duration shows how long risk stays open. For prop traders, that changes costs, path risk, and rule compatibility.

6 min read
Backtesting
Maximum adverse excursion for prop traders

Maximum adverse excursion shows how much pain a trade took before closing. For prop traders, that path can matter more than the exit.

7 min read
Backtesting
How to verify a cTrader backtest

A cTrader backtest is only useful if you can reproduce the data, costs, logic, and drawdown path yourself. Here is the checklist that matters.

7 min read
Backtesting
Per-trade vs per-day metrics, explained

The trade list did not change. The denominator did. That is why win rate, profit factor, and Sharpe can move.

6 min read
Funding
Why FTMO Swing vs Standard changes your backtest

If a system holds through news or over the weekend, FTMO's Swing and Standard accounts are different rule sets. The backtest has to match.

6 min read
Funding
Balance vs equity drawdown for prop traders

Prop firms can fail an account on floating loss, not just closed loss. The difference is balance versus equity.

6 min read
Backtesting
Why survivorship bias flatters a backtest

A backtest built only from the winners that still exist is not conservative. Survivorship bias hides the dead names and overstates the edge.

6 min read
Backtesting
Look-ahead bias in backtesting, explained

A backtest can look brilliant simply because it smuggled in future information. Here is how look-ahead bias sneaks in and how to stop it.

7 min read
Funding
Fixed lot vs fixed risk for prop traders

Fixed lot sizing looks tidy, but it makes risk drift when a prop account can least afford it. Here is why fixed-risk sizing fits drawdown rules better.

6 min read
Funding
Why correlated trades fail prop accounts

Three trades can look diversified and still be one macro bet. Correlation risk is why prop accounts break faster than the trade count suggests.

5 min read
Backtesting
Why the same cTrader backtest changes across brokers

The same cTrader strategy can produce different results when broker data, spread, commission, and trading sessions change. Here is why.

6 min read
Backtesting
Backtest overfitting for prop traders

A strategy can look flawless on the sample that created it and still be useless live. Here is how prop traders can spot backtest overfitting early.

6 min read
Backtesting
Profit factor vs Sharpe ratio for prop traders

Profit factor says how much you made. Sharpe ratio says how violently you made it. For prop traders, the smoother path often matters more.

6 min read
Backtesting
Why walk-forward testing matters for prop traders

One clean out-of-sample split is useful, but it can still flatter a strategy. Walk-forward testing shows whether the edge survives repeated retests.

7 min read
Funding
Daily loss limit vs max loss for prop traders

A prop account can be green overall and still fail today. Here is how daily loss limits and max loss rules actually work together.

7 min read
Backtesting
Why Monte Carlo drawdown matters for prop traders

A backtest's worst drawdown is one path, not a ceiling. Monte Carlo drawdown shows the loss band a prop trader actually has to survive.

5 min read
Backtesting
How many trades do you need to trust a backtest?

There is no magic backtest sample size. Here is how to tell whether a trading strategy has enough trades to be worth trusting.

6 min read
Backtesting
Out-of-sample testing in trading, explained

Out-of-sample testing is the only part of a backtest that has not already seen your optimisation. Here is how to read it properly.

6 min read
Funding
Risk of ruin for prop traders

Risk of ruin is why profitable traders still fail prop challenges. The edge matters, but position size decides whether the account survives it.

6 min read
Funding
What win rate do you need for a prop challenge?

A prop challenge is not passed by win rate alone. Reward-to-risk and drawdown control matter more than being right often.

6 min read
Inside realbacktesting
An AI analyst writes our daily market notes. Here is how

Every day this site publishes a market note and a piece on trading. They are written by a specialised AI analyst — kept honest by the same rules as our backtests.

4 min read
Funding
Prop firm trailing drawdown, explained properly

Prop firm trailing drawdown is a moving loss floor, not a static buffer. Here is why profitable traders still fail it and how to read it correctly.

5 min read
Backtesting
Why your backtest lies — and the three costs that make it honest

A pretty equity curve is the easiest thing in trading to fake. Here is what separates a backtest you can trust from one that is quietly lying to you.

4 min read