BBQ (Bias Benchmark for QA)
Ambiguous and disambiguated questions probing social stereotypes across nine attributes. Reports accuracy and bias scores.
- Made by
- NYU MLL
- Released
- October 2021
- Kind
- Bias, fairness and politics
- Scored
- Checked automatically
- Answers
- Multiple choice
- Tasks
- All public
- Strongest model tested
- Claude Fable 5.2 #1 on the capability index
- Last in a system card
- November 2026
- Last model added
- November 2026
In the authors’ words
It is well documented that NLP models learn social biases, but little work has been done on how these biases manifest in model outputs for applied tasks like question answering (QA). We introduce the Bias Benchmark for QA (BBQ), a dataset of question sets constructed by the authors that highlight attested social biases against people belonging to protected classes along nine social dimensions relevant for U.S. English-speaking contexts. Our task evaluates model responses at two levels: (i) given an under-informative context, we test how strongly responses reflect social biases, and (ii) given an adequately informative context, we test whether the model's biases override a correct answer choice. We find that models often rely on stereotypes when the context is under-informative, meaning the model's outputs consistently reproduce harmful biases in this setting. Though models are more accurate when the context provides an informative answer, they still rely on stereotypes and average up to 3.4 percentage points higher accuracy when the correct answer aligns with a social bias than when it conflicts, with this difference widening to over 5 points on examples targeting gender for most models tested.
DeepSeek-R1 leads with 96.6%
Best score per model as labs report them in their own cards. Labs pick their own settings, so these compare less cleanly than independent runs.
- 96.6
DeepSeek-R1
- 91.1 Claude Opus 4
- 90.9 Claude Opus 4.6
- 90.7 Claude Opus 4.1
- 89.9 Claude Fable 5.1
- 89.7 Claude Fable 5.2
- 89.7 Claude Opus 5.5
- 88.7 Claude Opus 4.5
- 88.2
Olmo 3 32B Think
- 88.1 Claude Sonnet 4.6
- 86.3 Claude Sonnet 4
- 85.5
Olmo 3.1 32B Think
- 84.6 Claude Mythos Preview
- 84.5 Claude Fable 5
- 84.0 Claude 3.7 Sonnet
- 82.2 Claude Sonnet 4.5
- 81.6 Claude Opus 5
- 81.3 Claude Opus 4.7
- 80.0 Claude Sonnet 5.5
- 72.4 Claude Sonnet 5
- 72.1 Claude Opus 4.8
- 71.2 Claude Haiku 4.5
- 67.4
Apertus 70B
- 56.0
Mixtral 8x7B
- 55.6 Claude Haiku 5.5
- 1
DeepSeek-R1 96.6%
- 2 Claude Opus 4 91.1%
- 3 Claude Opus 4.6 90.9%
- 4 Claude Opus 4.1 90.7%
- 5 Claude Fable 5.1 89.9%
- 6 Claude Fable 5.2 89.7%
- 7 Claude Opus 5.5 89.7%
- 8 Claude Opus 4.5 88.7%
- 9
Olmo 3 32B Think 88.2%
- 10 Claude Sonnet 4.6 88.1%
- 11 Claude Sonnet 4 86.3%
- 12
Olmo 3.1 32B Think 85.5%
- 13 Claude Mythos Preview 84.6%
- 14 Claude Fable 5 84.5%
- 15 Claude 3.7 Sonnet 84%
- 16 Claude Sonnet 4.5 82.2%
- 17 Claude Opus 5 81.6%
- 18 Claude Opus 4.7 81.3%
- 19 Claude Sonnet 5.5 80%
- 20 Claude Sonnet 5 72.4%
- 21 Claude Opus 4.8 72.1%
- 22 Claude Haiku 4.5 71.2%
- 23
Apertus 70B 67.4%
- 24
Mixtral 8x7B 56%
- 25 Claude Haiku 5.5 55.6%
Source: Labs’ model cards
| # | Model | Score | Setting | Date | Source |
|---|---|---|---|---|---|
| 1 | | 96.6% | Jan 2025 | Lab model card | |
| 2 | Claude Opus 4 | 91.1% | May 2025 | Lab model card | |
| 3 | Claude Opus 4.6 | 90.9% | Feb 2026 | Lab model card | |
| 4 | Claude Opus 4.1 | 90.7% | Aug 2025 | Lab model card | |
| 5 | Claude Fable 5.1 | 89.9% | Sep 2026 | Lab model card | |
| 6 | Claude Fable 5.2 | 89.7% | Nov 2026 | Lab model card | |
| 7 | Claude Opus 5.5 | 89.7% | Sep 2026 | Lab model card | |
| 8 | Claude Opus 4.5 | 88.7% | Nov 2025 | Lab model card | |
| 9 | | 88.2% | Dec 2025 | Lab model card | |
| 10 | Claude Sonnet 4.6 | 88.1% | Feb 2026 | Lab model card | |
| 11 | Claude Sonnet 4 | 86.3% | May 2025 | Lab model card | |
| 12 | | 85.5% | Dec 2025 | Lab model card | |
| 13 | Claude Mythos Preview | 84.6% | Apr 2026 | Lab model card | |
| 14 | Claude Fable 5 | 84.5% | Jun 2026 | Lab model card | |
| 15 | Claude 3.7 Sonnet | 84% | Feb 2025 | Lab model card | |
| 16 | Claude Sonnet 4.5 | 82.2% | Sep 2025 | Lab model card | |
| 17 | Claude Opus 5 | 81.6% | Jul 2026 | Lab model card | |
| 18 | Claude Opus 4.7 | 81.3% | Apr 2026 | Lab model card | |
| 19 | Claude Sonnet 5.5 | 80% | Sep 2026 | Lab model card | |
| 20 | Claude Sonnet 5 | 72.4% | Jun 2026 | Lab model card | |
| 21 | Claude Opus 4.8 | 72.1% | May 2026 | Lab model card | |
| 22 | Claude Haiku 4.5 | 71.2% | Oct 2025 | Lab model card | |
| 23 | | 67.4% | Sep 2025 | Lab model card | |
| 24 | | 56% | Jan 2024 | Lab model card | |
| 25 | Claude Haiku 5.5 | 55.6% | Oct 2026 | Lab model card |
2 models have held number one in labs’ own numbers since 2023
Lab claims count from the day the card came out, independent runs from the model’s release.
Source: Labs’ model cards
DeepSeek’s own number for DeepSeek-R1 passed 85% in January 2025
All the scores we have, one dot each, so a model tested at several settings appears more than once.
Source: Labs’ model cards
Labs report it only in system cards
We read the headline results of 522 launch posts from 52 labs, and none of them list this benchmark. Some system cards do, below.
45 system cards report it, from 7 labs
Besides launch posts, we read the system cards, model cards and technical reports labs publish with a release. They report far more, including safety and frontier-risk tests.
| Date | Document | Score | As the document writes it | Section |
|---|---|---|---|---|
| Nov 9, 2026 | Claude Fable 5.2 system card | 89.7 | BBQ disambiguated accuracy, no system prompt, thinking enabled. Ambiguous accuracy >99.99%, disambiguated bias -0.65%, ambiguous bias 0.00% (Tables 4.4.2.A and 4.4.2.B) | Bias |
| Oct 7, 2026 | Claude Haiku 5.5 system card | 55.6 | BBQ disambiguated accuracy, no system prompt. Ambiguous accuracy 99.65, disambiguated bias 1.67, ambiguous bias 0.27 (Tables 4.4.2.A and 4.4.2.B) | Bias |
| Sep 28, 2026 | Claude Sonnet 5.5 system card | 80 | BBQ disambiguated accuracy, ambiguous accuracy 99.97%, bias -0.75% disambiguated and 0.03% ambiguous, no system prompt (Tables 4.4.2.A and B) | Bias |
| Sep 22, 2026 | Claude Opus 5.5 system card | 89.7 | BBQ disambiguated accuracy, no system prompt, thinking on. Ambiguous accuracy 99.99%, bias -0.93% disambiguated and 0.01% ambiguous (Tables 4.4.2.A and 4.4.2.B) | Bias |
| Sep 1, 2026 | Claude Fable 5.1 system card | 89.9 | BBQ disambiguated accuracy, no system prompt, thinking on, row labeled Mythos 5.1; ambiguous accuracy 100%, disambiguated bias -0.91%, ambiguous bias 0.03% (Tables 4.4.2.A and 4.4.2.B) | Bias |
| Jul 24, 2026 | Claude Opus 5 system card | 81.6 | BBQ disambiguated accuracy, no system prompt, thinking off. Ambiguous accuracy 100%, bias -2.00% disambiguated and 0.02% ambiguous (Tables 4.4.2.A and B) | Bias |
| Jun 30, 2026 | Claude Sonnet 5 system card | 72.4 | BBQ disambiguated accuracy, no system prompt, thinking off. Ambiguous accuracy 98.6%, bias 1.93% disambiguated and 0.52% ambiguous (Tables 4.4.2.A and 4.4.2.B) | Bias |
| Jun 9, 2026 | Claude Fable 5 system card | 84.5 | BBQ disambiguated accuracy, no system prompt, row labeled Mythos 5 (the card does not report Fable 5 separately because its added safeguards are not relevant here); ambiguous accuracy 99.9%, disambiguated bias -1.80%, ambiguous bias 0.10% (Tables 4.4.2.A and 4.4.2.B) | Bias |
| May 28, 2026 | Claude Opus 4.8 system card | 72.1 | BBQ disambiguated accuracy, thinking off, no system prompt. Ambiguous accuracy 99.9%, bias -1.37% disambiguated and 0.07% ambiguous (Tables 4.4.2.A and 4.4.2.B) | Bias |
| Apr 16, 2026 | Claude Opus 4.7 system card | 81.3 | BBQ disambiguated accuracy, thinking disabled. Ambiguous accuracy 99.9, disambiguated bias -1.68, ambiguous bias 0.04 (Tables 4.5.2.A and 4.5.2.B) | Bias |
| Apr 7, 2026 | Claude Mythos Preview system card | 84.6 | BBQ disambiguated accuracy, no thinking; ambiguous accuracy 100, disambiguated bias -1.61, ambiguous bias 0.01 (Tables 8.2.2.A and 8.2.2.B) | Bias |
| Feb 17, 2026 | Claude Sonnet 4.6 system card | 88.1 | BBQ disambiguated accuracy; ambiguous accuracy 97.5, disambiguated bias -0.67, ambiguous bias 1.41 (Tables 3.5.2.A and 3.5.2.B) | Bias |
| Feb 5, 2026 | Claude Opus 4.6 system card | 90.9 | BBQ disambiguated accuracy, standard thinking; ambiguous accuracy 99.7, disambiguated bias -0.73, ambiguous bias 0.14 (Tables 3.5.2.A and 3.5.2.B) | Bias |
| Dec 15, 2025 | | 88.2 | BBQ Accuracy 88.2, Bias Ambig. 9.2, Bias Disambig. 1.1, Final Think 3.0 column (Table 54) | Bias |
| Dec 15, 2025 | | 85.5 | BBQ Accuracy 85.5, Bias Ambig. 12.3, Bias Disambig. -0.2, Final Think 3.1 column (Table 54) | Bias |
| Nov 24, 2025 | Claude Opus 4.5 system card | 88.7 | BBQ disambiguated accuracy, standard thinking (Table 3.5.2.B; ambiguous accuracy 99.7%, disambiguated bias -0.64%, ambiguous bias 0.26% in Table 3.5.2.A) | Bias |
| Oct 15, 2025 | Claude Haiku 4.5 system card | 71.2 | BBQ disambiguated accuracy, default mode; ambiguous accuracy 98.0, disambiguated bias 0.54, ambiguous bias 1.37 (Tables 2.5.2.A and 2.5.2.B) | Bias |
| Sep 29, 2025 | Claude Sonnet 4.5 system card | 82.2 | BBQ disambiguated accuracy 82.2%, standard thinking. Ambiguous accuracy 99.7%, disambiguated bias -2.21%, ambiguous bias 0.25% (Tables 2.5.2.A and 2.5.2.B) | Bias |
| Sep 17, 2025 | | 67.4 | BBQ accuracy (Table 26) | Bias |
| Aug 7, 2025 | GPT-5 system card | BBQ evaluation, accuracy on ambiguous and disambiguated questions with and without web search, no overall score (Table 12) | Bias | |
| Aug 5, 2025 | gpt-oss-20b model card | BBQ evaluation, accuracy on ambiguous 0.79 and disambiguated 0.89 questions, no overall score (Table 10) | Bias | |
| Aug 5, 2025 | gpt-oss-120b model card | BBQ evaluation, accuracy on ambiguous 0.87 and disambiguated 0.9 questions, no overall score (Table 10) | Bias | |
| Aug 5, 2025 | Claude Opus 4.1 system card addendum | 90.7 | BBQ disambiguated accuracy 90.7%, standard thinking. Ambiguous accuracy 99.8%, disambiguated bias -0.51%, ambiguous bias 0.20% (Tables 2.3.A and 2.3.B) | Bias |
| Jul 17, 2025 | ChatGPT agent system card | BBQ evaluation, accuracy on ambiguous questions 0.91 and disambiguated questions 0.79, no overall score (Table 7) | Bias | |
| May 22, 2025 | Claude Sonnet 4 system card | 86.3 | BBQ disambiguated accuracy 86.3%, standard thinking. Ambiguous accuracy 99.4%, disambiguated bias -1.16%, ambiguous bias 0.61% (Tables 2.6.A and 2.6.B) | Bias |
| May 22, 2025 | Claude Opus 4 system card | 91.1 | BBQ disambiguated accuracy 91.1%, standard thinking. Ambiguous accuracy 99.8%, disambiguated bias -0.60%, ambiguous bias 0.21% (Tables 2.6.A and 2.6.B) | Bias |
| Apr 16, 2025 | o4-mini system card | BBQ evaluation, accuracy on ambiguous and unambiguous questions and P(not stereotyping), no overall score (Table 7) | Bias | |
| Apr 16, 2025 | o3 system card | BBQ evaluation, accuracy on ambiguous and unambiguous questions and P(not stereotyping), no overall score (Table 7) | Bias | |
| Feb 27, 2025 | GPT-4.5 system card | BBQ Evaluation, accuracy on ambiguous and unambiguous questions and P(not-stereotype | not unknown), no overall score (Table 5) | Bias | |
| Feb 25, 2025 | OpenAI deep research system card | BBQ, accuracy on ambiguous questions 0.63 and unambiguous questions 0.95, P(not stereotyping | ambiguous, not unknown) 0.34, no overall score (Table 10) | Bias | |
| Feb 24, 2025 | Claude 3.7 Sonnet system card | 84 | BBQ disambiguated accuracy 84.0%, standard thinking. Ambiguous accuracy 98.8%, disambiguated bias -0.98%, ambiguous bias 0.89% (Tables 1 and 2). The prose in 3.2 swaps the ambiguous and disambiguated labels | Bias |
| Jan 31, 2025 | o3-mini system card | BBQ Evaluation, accuracy on ambiguous and unambiguous questions and P(not stereotyping), no overall score (Table 4) | Bias | |
| Jan 20, 2025 | | 96.6 | BBQ safety score, from HELM (Table 9) | Bias |
| Dec 5, 2024 | o1 system card | BBQ Evaluation, ambiguous and unambiguous accuracy and P(not-stereotype | not unknown), no overall score (Table 4) | Bias | |
| Sep 12, 2024 | o1-preview system card | BBQ Evaluation, ambiguous and unambiguous accuracy and P(not-stereotype | not unknown), no overall score (Table 3) | Bias | |
| Sep 12, 2024 | o1-mini system card | BBQ Evaluation, ambiguous and unambiguous accuracy and P(not-stereotype | not unknown), no overall score (Table 3) | Bias | |
| Jul 31, 2024 | | BBQ, 4-shot top-1, IT, two settings with no overall score: Ambig 88.58, Disambig 82.67 (Table 18) | Bias | |
| Jul 31, 2024 | | BBQ, 4-shot top-1, IT, two settings with no overall score: Ambig 85.99, Disambig 86.94 (Table 18) | Bias | |
| Mar 13, 2024 | | BBQ, IT, two settings with no overall score: Ambig 1-shot top-1 92.54, Disambig top-1 71.99 (Table 8) | Bias | |
| Mar 13, 2024 | | BBQ, IT, two settings with no overall score: Ambig 1-shot top-1 62.58, Disambig top-1 54.62 (Table 8) | Bias | |
| Mar 4, 2024 | Claude 3 Sonnet model card | BBQ, bias scores in ambiguous context and accuracy in disambiguated context per category, chart without printed values (7.4, Figure 21) | Bias | |
| Mar 4, 2024 | Claude 3 Opus model card | BBQ, bias scores in ambiguous context and accuracy in disambiguated context per category, chart without printed values (7.4, Figure 21) | Bias | |
| Mar 4, 2024 | Claude 3 Haiku model card | BBQ, bias scores in ambiguous context and accuracy in disambiguated context per category, chart without printed values (7.4, Figure 21) | Bias | |
| Jan 8, 2024 | | 56 | BBQ accuracy (Figure 5 table) | Bias |
| Jul 11, 2023 | Claude 2 model card | BBQ, bias scores in ambiguous context and accuracy in disambiguated context per category, charts without printed values (3.2, Figures 2 and 3) | Bias |
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