I let AI build a trading bot, then Reddit caught my overfitting mistake
Overfitting backtest: Two people on Reddit pushed back on my last post about testing 324 parameter combinations. Both were right, and their pushback turned into the most useful test I’ve run on this bot so far. Here’s what they said, what I did about it, and what the corrected numbers actually show including the uncomfortable parts.
- ▪Overfitting backtest: Two people on Reddit pushed back on my last post about testing 324 parameter combinations.
- ▪Both were right, and their pushback turned into the most useful test I’ve run on this bot so far.
- ▪Here’s what they said, what I did about it, and what the corrected numbers actually show including the uncomfortable parts.
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| Original publisher | AI Project Log |
| Canonical URL | https://aiprojectlog.com/overfitting-backtest/ |
| Publication time | Thu, 16 Jul 2026 19:24:06 +0000 |
| Retrieval time | 2026-07-16T20:44:36.365Z |
| Last seen | 2026-07-16T20:44:36.365Z |
| Headline source | Publisher (no WeSearch rewrite) |
| Excerpt source | publisher body |
| Excerpt method | First ~120 words (~800 chars) of extracted publisher body, fair-use limited. |
| Summary | WeSearch · cerebras-chat (WeSearch summarizer) |
| Summary source text | contentText |
| Citation coverage | Summary is a WeSearch-generated derivative; primary citation is the original publisher URL. |
| Cluster | US7X0mngKuqt |
| Cluster logic | Grouped by semantic title/content similarity across sources within a rolling window. Same-publisher template collisions are excluded from coverage comparison. |
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| Publisher visit | Yes — open original |
| Substitutes article? | No — link-out required for full text |
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| Indexing | May the item be indexed (stored, ranked, made findable)? | Allowed |
| Snippet | May a short excerpt of the publisher's text be shown? | Allowed |
| AI summary | May WeSearch generate its own short summary of the article? | Limited |
| Retrieval / RAG | May the content be exposed for third-party retrieval-augmented generation? | Not asserted |
| Model training | May the content be used to train AI models? | Not asserted |
| Commercial reuse | May the content be reused commercially? | Not permitted |
Basis: Derived from the published RSS/Atom feed. Contact: [email protected]. Reviewed: 2026-07-24.
Opening excerpt (first ~120 words) tap to expand
Overfitting backtest: Two people on Reddit pushed back on my last post about testing 324 parameter combinations. Both were right, and their pushback turned into the most useful test I’ve run on this bot so far. Here’s what they said, what I did about it, and what the corrected numbers actually show including the uncomfortable parts. The critique After I posted that the best of 324 backtested combinations returned +68.6%, someone pointed out the obvious flaw I’d skipped: testing 324 combinations against the same data and reporting the best one is a textbook multiple-comparisons problem. With enough combinations, something will look great by chance alone, whether or not there’s real signal underneath.
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Excerpt limited to ~120 words for fair-use compliance. The full article is at AI Project Log.
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