← @ashmehta

Why your backtest lied and also told the truth

ready · May 4, 9:28 PM · $2.90 total

Plan (drafter input)

planner market_mechanics

Ash breaks down why backtests always look better than live performance — not because traders cheat, but because the backtest has no market impact, no slippage model that actually fits, and no regime shift baked in. The specific beat: the moment you go live and discover your signal's edge was partly the bid-ask spread you weren't paying in the sim. Button: the backtest was telling you the truth. It just wasn't the truth about the future.

Timeless market mechanics take. No news hook needed. Speaks directly to the quant-curious audience who has hit this wall. Video format works — Ash delivers this kind of compressed corrective best in deadpan talking-head mode.

special_message: Plan ONE evergreen video. Format must be video. Pick a timeless on-pillar take that grounds the persona's voice — no current events, no news angle.

Script

Here's the thing. Your backtest didn't cheat. You didn't cheat. The math was right. [pause] The problem is the backtest exists in a frictionless universe. No market impact. No slippage model that fits your actual fill size. No regime shift baked in. [pause] And the specific thing nobody warns you about: part of your edge was the bid-ask spread you weren't paying in the sim. You were crossing it for free. Every trade. Two years of history. [pause] So you go live. You start paying it. The edge compresses. You think something broke. [pause] Nothing broke. The backtest was telling you the truth. It just wasn't the truth about the future. It was the truth about a world that doesn't have you in it.

Caption

your backtest was right. it just didn't include you. #quant #algotrading #backtesting #trading

Pipeline

  1. Voiceover done elevenlabs · eleven_v3
    Qmet1SuIMnIE_voice.mp3
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    api 21.8s
    media 54.4s
    May 4, 9:29 PM
  2. First-frame avatar done fal · fal-ai/flux-pro/kontext
    Qmet1SuIMnIE_first_frame.png
    $0.04
    api 43.0s
    May 4, 9:29 PM
  3. Final done heygen · heygen-v2-talking-photo
    Qmet1SuIMnIE_final.mp4
    $2.72
    api 153.5s
    media 45.3s
    May 4, 9:32 PM

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