GPT-NeoX 1.5B on TruthfulQA: score, rank and what it means
GPT-NeoX 1.5B scores 44.3 on TruthfulQA, placing it #599 of 600 models in the index. The benchmark average is 73.6 and the leader is GPT-5.1 Max at 91.1.
Score distribution
The chart shows the top 10 models on TruthfulQA, with GPT-NeoX 1.5B highlighted. Longer bars mean higher scores.
Top 10 leaderboard
| # | Model | Provider | Context | Input / 1M | Avg score |
|---|---|---|---|---|---|
| 1 | GPT-5.1 Max | OpenAI | 2000000 | $20.50 | 87.9 |
| 2 | Gemini 3 Pro Reasoning | Google DeepMind | 200000 | $19.69 | 87.5 |
| 3 | GPT-5.1 Reasoning | OpenAI | 400000 | $20.27 | 88.3 |
| 4 | GPT-5.2 Pro | OpenAI | 2000000 | $21.32 | 89.6 |
| 5 | GPT-5.2 | OpenAI | 2000000 | $19.71 | 88.0 |
| 6 | Gemini 3 Pro Max | Google DeepMind | 2000000 | $20.57 | 87.9 |
| 7 | Grok 4 Reasoning | xAI | 2000000 | $19.67 | 87.8 |
| 8 | Qwen3-Max Max | Alibaba Cloud | 400000 | $18.53 | 85.9 |
| 9 | GPT-5.1 | OpenAI | 2000000 | $19.01 | 86.0 |
| 10 | GPT-5.1 Turbo | OpenAI | 2000000 | $19.19 | 86.1 |
What this score means
On TruthfulQA, GPT-NeoX 1.5B sits at #599 of 600. The leader, GPT-5.1 Max, scores 91.1, so the gap to the top is 46.8 points. The median model in this index scores 76.3, which puts GPT-NeoX 1.5B below the midpoint.
EleutherAI models average 58.5 on this benchmark. GPT-NeoX 1.5B is 14.2 points below that provider line, so it is a weaker result than the average EleutherAI model.
Among small open-weight models, the average is 59.9. GPT-NeoX 1.5B is 15.6 points below that group. This is the more useful comparison if you are shortlisting within the same tier rather than across the whole index.
Read a 44.3 as a relative signal, not an absolute guarantee. Benchmark scores depend on prompt format, evaluation harness and contamination controls. Use this page to narrow the shortlist, then test the model on your own data.
Price context
At $0.060 per million input tokens, GPT-NeoX 1.5B is below the median input price of $4.00 across the 600 models scored on TruthfulQA. The models immediately around it in the ranking are shown below so you can compare score and price together.
| Model | Provider | Context | Input / 1M | Avg score |
|---|---|---|---|---|
| Molmo 1.5B | Allen Institute for AI | 8192 | $0.21 | 42.8 |
| Zephyr 1.5B | Hugging Face | 32768 | $0.10 | 38.0 |
| Pythia 7B | EleutherAI | 8192 | $0.10 | 40.7 |
| Pythia 1.5B | EleutherAI | 4096 | $0.10 | 35.8 |
| GPT-NeoX 1.5B | EleutherAI | 32768 | $0.06 | 36.4 |
| SmolLM3 1.5B | Hugging Face | 8192 | $0.04 | 36.8 |
Other benchmarks for GPT-NeoX 1.5B
| Benchmark | Score | Rank | Percentile | Relative |
|---|---|---|---|---|
| MMLU-Pro | 47.0 | 598 | 1th | |
| GPQA Diamond | 32.4 | 598 | 1th | |
| SWE-bench Verified | 18.3 | 600 | 1th | |
| HumanEval | 37.0 | 600 | 1th | |
| MATH-500 | 35.7 | 597 | 1th | |
| AIME 2025 | 17.6 | 598 | 1th | |
| LiveCodeBench | 22.0 | 598 | 1th | |
| IFEval | 49.5 | 600 | 1th | |
| HellaSwag | 58.1 | 598 | 1th | |
| MMMU | 38.6 | 598 | 1th | |
| Arena Elo | 1112.0 | 596 | 1th |
FAQ
What score does GPT-NeoX 1.5B get on TruthfulQA?
GPT-NeoX 1.5B scores 44.3 on TruthfulQA in this index. The benchmark average is 73.6 and the top score is 91.1.
How does GPT-NeoX 1.5B rank on TruthfulQA?
It ranks #599 of 600 models, in the 1st percentile. The leader is GPT-5.1 Max at 91.1.
Is GPT-NeoX 1.5B good at TruthfulQA?
It is below the median for this benchmark, so test it carefully before relying on it for this capability. The result should be read alongside its price and context window.
How is the TruthfulQA score calculated?
TruthfulQA is a safety benchmark. Scores in this index are modelled estimates on a 0–100 scale (or Elo for Arena), derived from capability tier and benchmark difficulty. They are not official leaderboard results.
What does GPT-NeoX 1.5B cost?
GPT-NeoX 1.5B costs $0.060 per million input tokens and $0.32 per million output tokens.