Honest trading research

17 Biases That Wreck Your Trading

Three lenses. 10 methodology biases that lie to you through your backtest. 1 meta-bias sitting under all of them. 6 behavioral biases that fire when real money is on the line. Every one defeated with real data and real case studies.

10 methodology biases1 meta-bias6 behavioral biases22 deep-dives published

Before anything else

We can't claim to be bias-free. Nobody can.

Every one of these 17 biases applies to us too. The meta-bias especially, the one where every backtest silently assumes the future will resemble the past. We cannot escape it. Neither can you.

What we CAN do is three things, and we commit to all three.

1Apply the methodology to ourselves. Walk-forward testing, out-of-sample checks, parameter-robustness sweeps — the same rigor we demand of any strategy we review.
2Document our failures in public. Every retired bot, every strategy that looked great until we ran the honest version, every walk-forward disaster. All on the Post-Mortems page.
3Name the meta-bias honestly. Every backtest number on BearBullRadar carries a "past ≠ future" caveat. Not as a disclaimer. As a structural fact we build around.

Free PDF

The 17 Biases That Wreck Your Trading

The complete field guide in one PDF: 10 backtest traps, 1 meta-bias under all of them, and 12 behavioral biases that make you override the bot. Condensed from my 200-strategy test and six years of live bots.

The 10 Deadliest Biases in Trading Backtests — Plus the One Under All of Them

⭐ Pillar Article

Start here

The 10 Deadliest Biases in Trading Backtests — Plus the One Under All of Them

How I watched my colleague Sandra's backtest print +510% — then shrank to +28% when I tested it honestly.

Read the full pillar16 min read

Part I · 10 Methodology Biases

How your backtest lies

Before the market can beat you, your own backtest will. These ten biases are the reason most published returns are fiction.

Survivorship Bias

Picking winners after they won

Look-Ahead Bias

Using tomorrow's data to predict today

Hindsight Bias

"It was obvious, wasn't it?"

Overfitting

The bot that memorized the answers

Cherry Picking

Only showing your wins

Confirmation Bias

Saving only what you like

P-Hacking

Test enough, something "works"

Regime Bias

Bull-only testing

Recency Bias

Last year's winners = next year's?

Data-Snooping

Tuning parameters until it fits

Plus 5 methodology extensions: Beat HODL · Parameter Robustness · Benchmark Tunnel Vision · Sharpshooter Post-Mortem · Methodology page →

Part II · The Meta-Bias · Applies to ALL of the above

The Past Is Not the Future.
The one bias every backtest carries.

Even a backtest that passes all 10 methodology checks above is still testing on historical data. The future is a regime we haven't fully observed. Walk-forward catches regimes we've seen. It cannot catch regimes that haven't happened yet.

Hume called it the induction problem. Taleb called it the turkey problem. We call it the bias under all the others.

Read the meta-bias

All deep-dives

One bias per article. Real case studies. Honest data.

22 published

Trading Bias14 min

The 1%: What Profitable Traders Actually Do (Spoiler: Not Candlestick Patterns)

I tested 200+ strategies. Most were technical analysis. The data broke my assumptions.

17 Biases That Wreck Your Trading

We can't claim to be bias-free. Nobody can.

The 17 Biases That Wreck Your Trading

The 10 Deadliest Biases in Trading Backtests — Plus the One Under All of Them

How your backtest lies

The Past Is Not the Future.The one bias every backtest carries.

All deep-dives

The 1%: What Profitable Traders Actually Do (Spoiler: Not Candlestick Patterns)

My Friend Made 4x on a Memecoin in Two Weeks. I Made 12% That Month on a Boring Bot. Here's the Math He Didn't Do.

Your Day-Trading Profit Looks Great Until You Count the Hours

The Bias-Resistance Checklist: 24 Questions to Catch Yourself BEFORE the Damage

Data-Snooping: 3.2 Million Parameter Combinations. Your "Winner" Is Noise.

Recency Bias: Why Last Year's Winners Usually Lose Next Year

The Past Is Not the Future: The One Bias Every Backtest Has

Regime Bias: When Your Strategy Works in Bulls and Only Bulls

Overconfidence: Your First 3 Winning Trades Are the Most Dangerous

P-Hacking: 20 Random Strategies. One Looks Brilliant. By Luck Alone.

Anchoring: $100k Bitcoin Is Cheap (Said Everyone at $69k)

The Broker-Signal Trap: When Your Exchange Sends You Signals, You're Already Late

Sunk Cost: 3 Years of XRP and the Most Expensive Feelings in Crypto

Confirmation Bias: I Built 8 Strategy Variants. 6 Failed. Here's Why You Saw One.

Cherry Picking: The YouTube Guru Who Only Shows You 2020

Overfitting: Our Best Bot Made +45%, Then Lost 27% on Real Data

Hindsight Bias: Why NVIDIA Was "Obvious" (Only After It Won)

FOMO: The $140,000 Tax I Paid Between 2019 and 2023

Look-Ahead Bias: When Your AI Knows Tomorrow's Newspaper

Survivorship Bias: How Sandra's 14 "Perfect" Stocks Hid 12 Losers

Loss Aversion: Why Sandra Sold Every Winner Too Early

Why You Are Your Own Worst Enemy: 12 Behavioral Biases That Cost Retail Traders Everything

How you lie to yourself

Two more costs nobody reports

Every retired bot, every failure, documented publicly

TheBot-Letter

The Past Is Not the Future.
The one bias every backtest carries.