backtesting
Paper Trading vs Backtesting: What Each One Can and Cannot Prove
Both look like validation. Neither is sufficient alone. Here's exactly what each test can and cannot prove — and why confusing them costs traders real money.
Wolfgang Lämmle
stock picking
Are Stock Picking Services Worth It? How to Test One Before You Subscribe
Most stock picking services sell you a backtest disguised as a track record. Here's the buyer's checklist to tell the difference before you hand over a cent.
risk management
Drawdown Recovery Percentage: The Math That Makes Big Losses Almost Impossible to Escape
A 50% drawdown doesn't need a 50% gain to recover — it needs 100%. The math is asymmetric, it compounds against you, and most traders never look at it clearly until it's too late.
metrics
Sharpe Ratio vs Sortino Ratio vs Calmar Ratio: Which Risk-Adjusted Metric Should You Actually Optimize For?
Three metrics, three different definitions of risk — and optimizing for the wrong one can make a losing strategy look brilliant. Here's which one actually matters for your strategy.
backtesting
How to Read a Strategy Vendor's Backtest Without Getting Fooled
Most strategy vendors sell you the backtest they want you to see. Here's the systematic checklist that exposes what they're hiding.
Backtest Validity
Slippage Is Quietly Killing Your Backtest's Edge: How to Model It Honestly
Your backtest looks great — until you actually trade it. Slippage is the silent tax that turns winning strategies into losers, and most backtests ignore it almost entirely.
backtesting
I Tested the Golden Cross on Every Major Asset Class. Here Is What the Data Actually Shows.
The golden cross is one of the most cited signals in retail trading. We ran the numbers — commission-adjusted, out-of-sample, across four asset classes — so you don't have to take anyone's word for it.
backtesting
Probability of Backtest Overfitting: How to Quantify Whether Your Strategy Was Lucky
Suspecting your backtest is overfit is not the same as knowing. The PBO score turns that suspicion into a number — here's how it works and what to do with it.
statistics
The Deflated Sharpe Ratio: Why Your Strategy's Sharpe of 2.1 Is Probably Noise
A Sharpe of 2.1 sounds bulletproof. The Deflated Sharpe Ratio shows it's probably not. Here's the math that exposes why.
verdicts
I Tested the RSI(2) Mean-Reversion Strategy. Here's the Honest Verdict.
RSI(2) is one of the most cited mean-reversion setups in retail trading. We ran it through rigorous, multiple-testing-corrected validation to find out whether any real edge survives.
backtesting
P-Hacking Your Backtest: How Traders Fool Themselves with Statistics
Run enough backtests and you'll find a 'winning' strategy by pure chance. That's not edge — that's p-hacking, and it's more common than you think.
Walk-Forward Analysis
Walk-Forward Analysis: The Right Way to Validate a Trading Strategy
A single in-sample/out-of-sample split feels rigorous — it isn't. Walk-forward analysis is the only test that mimics how a strategy actually ages in the market.