Satcove Research · Benchmark of 22 October 2026

AI Consensus Is a Signal, Not a Scoreboard

We ran 2,500 questions with known answers through up to six AI models. Agreement tracked correctness, but unanimity was not proof.

By Satcove Research · Published · Exploratory, not peer reviewed

The short answer

AI agreement is a useful signal, not proof.

We asked up to six AI models 2,500 questions with known answers.

  • When they all gave the same answer, it was right 94.0% of the time (1,148 of 1,221).
  • Yet 73 of those unanimous answers were wrong.
  • When they split and agreement fell below 60%, the majority was right only 33.5% of the time.

So Satcove reads agreement as a signal, and disagreement as a reason to verify.

On this page

Key Findings

Four results carry the study: how often unanimous answers were right, how often they were wrong, how fast accuracy fell when models split, and how the majority compared with the best single model.

2,500

questions with a known answer

MMLU-Pro, TruthfulQA, PubMedQA, GPQA Diamond

94.0%

of unanimous answers were correct

1,148 of 1,221 unanimous questions

73

unanimous answers were wrong

6.0% of unanimous questions

33.5%

majority accuracy below 60% agreement

194 questions with a majority; 197 ties

  • Measured: the more the models agreed, the more often the majority answer matched the known answer, from 94.0% (unanimous) down to 33.5% (weak agreement).
  • Measured: on the 2,303 questions that had a majority, the majority scored 77.1% and Claude alone 77.5%. The majority did not clearly beat the strongest single model.
  • Interpretation: the value of several models is less a higher score than a visible signal: how much they agree, where they split, and what to verify.

Agreement Tracks Accuracy, but Does Not Guarantee It

When all models gave the same answer, it was correct 94.0% of the time. Majority accuracy then fell to 70.5%, 56.2% and 33.5% as agreement weakened. This is an association measured on multiple-choice questions, not proof that agreement causes accuracy.

Majority accuracy by agreement level (percent of questions where the majority answer matched the known answer)

Unanimous: 94.0%

1,221 questions · 1,221 with a majority answer · 1,148 correct · 95% CI 92.5–95.2%

Every answering model gave the same letter. This is the strongest agreement signal, and still not a guarantee.

See the 73 unanimous answers that were wrong →

Higher agreement means the panel converged more. It is a useful signal, not a guarantee. Final data, including second-pass answers. Jury of 4 to 6 models per question. Wilson 95% intervals.

Majority accuracy by agreement level
Agreement levelQuestionsWith a majorityCorrectAccuracy95% interval
Unanimous1,2211,2211,14894.0%92.5–95.2%
Strong agreement (80% or more)44044031070.5%66–74.5%
Clear majority (60-79%)44844825256.2%51.6–60.8%
Weak agreement or tie (under 60%)3911946533.5%27.2–40.4%

Source: benchmark dataset, final data including second-pass answers. Accuracy is computed on questions with a majority answer; the 197 exact ties all fall in the weak-agreement row and are excluded from its accuracy. Intervals are Wilson 95%.

73 Times, Every Model Was Wrong Together

A false consensus is a question where every answering model gave the same wrong answer. It happened 73 times in 2,500 questions: 44 in MMLU-Pro, 15 in TruthfulQA, 9 in PubMedQA and 5 in GPQA Diamond. Unanimity raises confidence. It does not remove shared blind spots.

Why it matters. These are the cases a majority-only view cannot flag: every model agreed, so nothing looked uncertain.

12 of 73 cases

  • MMLU-Pro · math

    5 models all answered D

    Correct answer: H

  • MMLU-Pro · other

    5 models all answered C

    Correct answer: B

  • MMLU-Pro · philosophy

    5 models all answered I

    Correct answer: B

  • MMLU-Pro · physics

    6 models all answered A

    Correct answer: F

  • MMLU-Pro · other

    5 models all answered A

    Correct answer: D

  • MMLU-Pro · other

    5 models all answered C

    Correct answer: D

  • MMLU-Pro · philosophy

    5 models all answered B

    Correct answer: I

  • MMLU-Pro · philosophy

    5 models all answered A

    Correct answer: D

  • MMLU-Pro · physics

    6 models all answered A

    Correct answer: C

  • MMLU-Pro · psychology

    5 models all answered F

    Correct answer: A

  • GPQA Diamond · chemistry

    5 models all answered B

    Correct answer: A

  • GPQA Diamond · chemistry

    5 models all answered D

    Correct answer: B

Why can't you open the question? We have not been able to confirm that the source question sets allow us to republish their text, and GPQA asks not to publish its questions at all. So each card shows only the source, the topic, how many models answered and the letters. The full list, with every model's letter, is in the downloadable answers file.

Unanimous answers that were wrong, by source
SourceUnanimousWrongShare wrong
GPQA Diamond43511.6%
MMLU-Pro696446.3%
PubMedQA12797.1%
TruthfulQA (mc1)355154.2%

Source: benchmark dataset, final data. GPQA rests on 43 unanimous questions, so its percentage is imprecise.

Model Results: Scope Matters More Than Rank

Single-model accuracy ranged from 63.6% to 74.7%, but the models did not all answer the same questions, and some scores include second-pass answers. Perplexity answered a separate 533-question sample, so it must not be read against the others on 2,500 questions. This is not a leaderboard.

Single-model accuracy on its own question set
ModelVersion testedQuestions answeredAccuracy95% intervalNotes
Claudeclaude-sonnet-4-62,50074.7%73–76.4%Includes 475 recovered answers
Geminigemini-3.5-flash-lite2,49969.9%68.1–71.7%Includes 85 recovered answers
Mistralmistral-large-latest2,49967.5%65.6–69.3%Includes 7 recovered answers
GPTgpt-4o-2024-08-062,50063.8%61.9–65.7%No recovered answers
Grokgrok-4.20-0309-non-reasoning2,50063.6%61.7–65.5%Includes 1 recovered answer
Perplexitysonar53370.0%66–73.7%Run on 533 questions only; includes 86 recovered answers

Source: benchmark dataset, final data. Letter-only multiple choice; model versions are the exact identifiers returned by each API on 22 October 2026. Four of the six identifiers are undated aliases. These versions are not necessarily the models in Satcove's current panel.

Same 533 questions for all six models
ModelCorrectAccuracy95% interval
Claude409 / 53376.7%73–80.1%
Gemini382 / 53371.7%67.7–75.3%
Perplexity373 / 53370.0%66–73.7%
Mistral366 / 53368.7%64.6–72.5%
Grok353 / 53366.2%62.1–70.1%
GPT341 / 53364.0%59.8–67.9%

Source: benchmark dataset, final data, questions where Perplexity and every other model gave a valid letter (533). This is the only fair comparison that includes Perplexity.

Why second-pass answers matter. 654 answers came from a second pass for replies that had no usable letter. They were right less often than first-pass answers: Claude 46.9% on 475 recovered answers against 81.2% on 2,025 first-pass answers. The first pass failed mostly on hard questions, so Claude's overall score depends on this mechanism. We report both views.

Majority Vote vs. the Best Single Model

Not clearly. On the 2,303 questions where a majority existed, the majority answer was right 77.1% of the time and Claude alone 77.5%. Counting the 197 ties as failures, the majority drops to 71% on all 2,500 questions.

Majority answer vs. the strongest single model
MeasureQuestionsCorrectAccuracy
Majority answer (ties excluded)2,3031,77577.1%
Claude on the same questions2,3031,78577.5%
Majority, ties counted as failures2,5001,77571%

Source: benchmark dataset, final data. The majority is computed on 2,303 questions (ties excluded); individual scores in the first table cover 2,500 questions. Claude's figure here is restricted to the same 2,303 questions.

On this benchmark, majority voting performed essentially on par with the strongest individual model rather than clearly surpassing it. The case for comparing several models is therefore not a higher raw score. It is that one model does not tell you when it is wrong, and agreement among several does tell you how much to check.

Not Every Question Had Six Voters

The number of models answering varied: five on 1,965 questions, six on 533 and four on 2. A unanimity of five is easier to reach than a unanimity of six, so we also report a constant jury of five and a constant jury of six. The conclusion holds in both.

1,965

questions answered by 5 models

Claude, GPT, Gemini, Mistral and Grok.

533

questions answered by 6 models

The same five plus Perplexity.

Why not six everywhere? Perplexity ran on a fixed sample of 533 questions instead of all 2,500, to limit cost. Two further questions had only four valid answers, so they are counted in the totals but not shown here.

Robustness checks on jury and protocol
ViewQuestionsMajority accuracyUnanimousUnanimous wrong
Headline: final data, 4 to 6 models2,50077.1%1,22173 (6.0%)
Constant jury of 52,49877.2%1,23580 (6.5%)
Constant jury of 6 (Perplexity questions)53377.6%25913 (5%)
Robustness: first-pass answers only2,46076.7%1,24086 (6.9%)

Source: benchmark dataset. Constant jury of 5: Claude, GPT, Gemini, Mistral and Grok, questions where all five gave a letter. Constant jury of 6: the 533 questions Perplexity answered. First-pass view removes the 654 second-pass answers, so some questions drop below four voters; that view is easier than the full set because missing answers concentrate on hard questions.

Our headline results use the full protocol, including format-recovery passes. We also report a protocol-only robustness check; it leads to the same substantive conclusion (93.1% of unanimous answers correct without recovery, 94.0% with). Of the 1,221 unanimous questions, 71 include a second-pass answer, and so do 5 of the 73 false consensuses. Satcove reports agreement by jury size rather than treating every question as a six-model vote.

Source and Topic Results: Read Them Together

Agreement and accuracy varied sharply by source: majority accuracy was 55.2% on GPQA Diamond, 74.4% on MMLU-Pro, 84.2% on PubMedQA and 89.2% on TruthfulQA. Topics are shown only inside their source, because the same topic name mixes sets of different difficulty.

Majority accuracy and unanimous errors by source and topic
SourceTopicQuestionsMajority accuracyUnanimousUnanimous wrong
GPQA Diamondbiology19small sample7small sample
GPQA Diamondchemistry9350.7%18small sample
GPQA Diamondphysics8654.9%18small sample
MMLU-Probiology11488.3%884
MMLU-Probusiness11562.2%24small sample
MMLU-Prochemistry11551.1%20small sample
MMLU-Procomputer science11574.8%493
MMLU-Proeconomics11482.9%735
MMLU-Proengineering11473.1%310
MMLU-Prohealth11285.2%804
MMLU-Prohistory11475%6510
MMLU-Prolaw11465.4%29small sample
MMLU-Promath11462.5%15small sample
MMLU-Proother11477%594
MMLU-Prophilosophy11485%614
MMLU-Prophysics11463.7%24small sample
MMLU-Propsychology11487.6%781
PubMedQAmedical20284.2%1279
TruthfulQA (mc1)misconceptions50389.2%35515

Source: benchmark dataset, final data. Cells with fewer than 30 questions, or fewer than 30 unanimous questions, hide the percentage (small sample). MMLU-Pro covers 1,597 of the 2,500 questions (63.9%), so it weighs heavily on overall figures. TruthfulQA and PubMedQA each form a single topic.

What This Benchmark Does Not Prove

It does not show that agreement proves truth, that Satcove's verdicts are more accurate than a single model's, or why models fail together. It measures how often a majority matched a known answer on 2,500 multiple-choice questions, and how that changed with agreement.

  • Agreement is not proof.

    73 questions were answered identically by every model and all 73 were wrong.

  • Multiple choice, one letter.

    The test measures option selection. It does not measure free-text reasoning or the way Satcove synthesizes an answer.

  • Truncated, not random.

    The 2,500 questions are the first 2,500 of a 2,997-question file. MMLU-Pro supplies 1,597 of them (63.9%), so it weighs heavily on every overall figure.

  • Variable jury.

    Five models answered 1,965 questions, six answered 533 and four answered 2. Perplexity answered a fixed 533-question sample.

  • Versions and recovery passes shape the scores.

    654 answers came from a second pass with a different protocol per model. Four of the six model identifiers are undated aliases.

  • Topic results mix sources.

    Physics, chemistry and biology combine GPQA Diamond and MMLU-Pro, and several cells hold fewer than 30 questions.

  • No reading of position bias.

    Questions have between 2 and 10 options and each source distributes correct answers differently, so letter frequencies cannot be read as a model bias.

  • One answer per model per question.

    The test cannot measure how stable an answer is across repeated runs.

  • No independence or contamination test.

    We do not know why models agree. The public question sets may also appear in training data. Neither point was tested.

From Disagreement to Decision

A single AI answer does not tell you when to doubt it. Satcove sends a question to several models, each answering separately, measures how much they align, names where they differ and suggests what to verify before you act. The benchmark supports reading agreement as a signal; it does not test Satcove's free-text verdicts.

Illustration (not benchmark data)

  1. STEP 1

    Question

    One question goes to several models.

  2. STEP 2

    Separate model answers

    Each model answers on its own, with no view of the others.

  3. STEP 3

    Agreement analysis

    Satcove measures how far the answers align.

  4. STEP 4

    Named disagreements

    Points where models differ are listed, not averaged away.

  5. STEP 5

    Next verification step

    The verdict says what to check before acting.

  6. STEP 6

    Agreement signal

    You read the answer together with its level of agreement.

  • Claude: Answer A
  • GPT: Answer A
  • Gemini: Answer B
  • Mistral: Answer A
  • Perplexity: Answer B
  • Grok: Answer A

Named disagreement. The two dissenting models stay visible, with the point where they differ. A card says what to verify before acting. The split is not averaged away.

Related: does AI consensus prove truth, how often AI models agree, our 75-question disagreement report, AI answer reliability, Satcove Open, false consensus, agreement score and when not to use multi-AI consensus.

Methodology

Each model received every question once, with the same instruction to reply with a single option letter, in a fresh conversation. We compared the letters with the known answer and measured agreement as the share of the jury giving the majority letter. Full definitions and scripts are published.

Date
22 October 2026. Calls ran the same day.
Questions
2,500 multiple-choice questions with a known answer: 1,597 MMLU-Pro, 503 TruthfulQA (mc1), 202 PubMedQA, 198 GPQA Diamond. Drawn with a fixed seed within each source.
Truncation
The question file holds 2,997 questions. We asked the first 2,500 in file order, then stopped. This is a truncation, not a random draw: no PubMedQA question from the second batch and 97 second-batch TruthfulQA questions were asked. As a result MMLU-Pro makes up 63.9% of the questions and weighs heavily on overall figures. Within each source the draw is reproducible.
Models and versions
Claude claude-sonnet-4-6, GPT gpt-4o-2024-08-06, Gemini gemini-3.5-flash-lite, Mistral mistral-large-latest, Perplexity sonar (with web search; the other models had none), Grok grok-4.20-0309-non-reasoning.
Jury
Up to six models. Five answered 1,965 questions, six answered 533, four answered 2. Perplexity answered a fixed 533-question sample to limit cost. A question needs at least four valid answers.
Valid answer
A reply that starts with the option letter. Prose is never interpreted as an answer, and a missing answer is not counted as wrong.
Majority, agreement, unanimity
The majority is the most frequent letter; an exact tie has no majority and is excluded from majority accuracy, then counted as a failure in the second figure. Agreement is the majority's share of the jury. Unanimity means all answering models gave the same letter.
Recovery pass
When a first-pass reply had no usable letter (prose, truncation or an API error), we asked again for that cell only, with a protocol adapted to each model: a forced letter choice for Claude (475 answers), a longer output limit for Perplexity (86), constrained output for Gemini (85) and a plain retry for Mistral and Grok (7 and 1). In total 654 answers in the final data come from this second pass. We report first-pass-only results separately.
Statistics
Wilson 95% intervals. No significance tests across models, and no repeated runs.
Not done
No test of independence between models, no test for training-data contamination, no reading of letter-position patterns.

Provenance

Checksums let you confirm that the files you download are the ones behind this page. Run shasum -a 256 file and compare.

Show SHA-256 checksums
Answers file
3ba8d9a7c5f900937f80f53a28bff6943358ed4e093e192cac06952fe4bc6024
Source workbook
14c33d4b5730b70f0e1c0f7c17caa2bfe9084ce1f761b45d40db027d12080ced
Rights
All rights reserved. Aggregate results and analysis artifacts are provided for verification; question texts are not redistributed. We could not confirm the licences of the source question sets (MMLU-Pro, TruthfulQA, PubMedQA, GPQA), so we publish option letters and ids only.
How to cite
Satcove Research, "AI Consensus Benchmark", 22 October 2026, satcove.com/research/ai-consensus-benchmark.

Download the Data and Scripts

Every figure on this page can be recomputed from the answers file. The files below include the claims list, the second-pass cells, the analysis script and checksums. No question text, prompt, key or user data is included.

Benchmark artifacts
FileContentsSize
ai-consensus-benchmark-2026-10-22-answers.csvAnswers by question: every model's letter, majority, agreement (2,500 rows, no question text)150 KB
claims.csvEvery claim used on this page, with its source and calculation6 KB
recovered_cells.csvThe 654 answers that came from the second pass34 KB
metrics_no_recovery.jsonMetrics from first-pass answers only6 KB
recovery_impact.csvFirst-pass vs. second-pass accuracy by model1 KB
jury_sensitivity.csvResults by jury size and constant jury1 KB
equal_footprint.csvModels compared on identical questions2 KB
source_by_topic.csvSource × topic table with small-sample flags2 KB
definitions.mdDefinitions: jury, majority, unanimity, recovery, false consensus3 KB
v1_analysis.pyAnalysis script (pandas)9 KB
build_recovered_cells.pyScript that lists second-pass cells (reads private run logs)2 KB
SHA256SUMS.txtSHA-256 checksums of every file1 KB

Open each file directly. SHA-256 values are also in SHA256SUMS.txt.

Frequently Asked Questions

Short answers on what agreement between AI models can and cannot tell you, based on this benchmark.

Does agreement between AI models mean the answer is correct?

No. In our benchmark, unanimous answers were correct 94.0% of the time (1,148 of 1,221 questions), so agreement is a strong signal, but 73 unanimous answers were wrong. Agreement shows that models converged, not that anyone checked the facts. Models can share the same blind spot. Treat agreement as a reason for more confidence, and keep verifying anything with real consequences, such as a medical, legal or financial decision.

How often are unanimous AI answers wrong?

In our test, 73 of 1,221 unanimous questions were unanimously wrong, or 6.0%. The rate differed by source: 4.2% for TruthfulQA, 6.3% for MMLU-Pro, 7.1% for PubMedQA and 11.6% for GPQA Diamond, although GPQA rests on only 43 unanimous questions. This is the rate on these multiple-choice questions, with up to six models answering (five on most questions). It is not a general error rate for AI.

What does low agreement between AI models mean?

It means the models split. When agreement fell below 60%, the majority answer was correct only 33.5% of the time (194 questions with a majority; 197 more ended in an exact tie). On those questions, no single answer was a reliable guide. Low agreement does not say which model is right. It says the question is contested, hard or ambiguous, and that the answer needs checking against a source before you rely on it.

Can multi-AI consensus replace fact-checking?

No. Consensus tells you where to look, not what is true. In our benchmark the majority answer was correct 77.1% of the time on the 2,303 questions where one existed, and 71.0% across all 2,500 questions when ties count as failures. Claude alone scored 77.5% on the same 2,303 questions. Agreement is useful for triage: high agreement lowers the priority of a check and disagreement raises it. Facts that matter still need a primary source.

Why can ChatGPT, Claude and Gemini make the same mistake?

We did not test the cause, so this is a hypothesis, not a finding. Plausible reasons include overlapping training data, similar training methods, misconceptions common in the text the models learn from, and question wording that pulls toward the same wrong option. Our data only shows that it happens: on 73 questions every answering model chose the same wrong answer. We tested GPT-4o, Claude Sonnet 4.6 and Gemini 3.5 Flash-Lite through their APIs, not the consumer apps.

When should you verify an AI answer?

Verify when models disagree, when the stakes are high, and when the answer rests on one claim you cannot easily judge, such as a date, a dose, a legal citation or a price. In our test, majority accuracy fell to 56.2% for clear majorities (60-79% agreement) and 33.5% below 60%. Even unanimous answers were wrong 73 times. Checking a primary source costs little compared with acting on a shared error.

What is a false consensus in multi-AI systems?

A false consensus is a question where every model that answered gave the same answer and that answer was wrong. We found 73 among 2,500 questions: 44 in MMLU-Pro, 15 in TruthfulQA, 9 in PubMedQA and 5 in GPQA Diamond. They matter because agreement looks like confirmation. A system that reports only a majority hides these cases. The safeguard is to read the agreement level together with the stakes, and to check what matters against an external source.

How does Satcove use disagreement between AI models?

Satcove sends one question to several models, each answering separately, then shows an agreement score and names the points where the models differ, with a next step to verify. When models split, the verdict says so instead of averaging the differences away. This benchmark tested simple letter agreement on multiple-choice questions, not Satcove's free-text synthesis. It supports reading agreement as a signal; it does not measure the accuracy of a Satcove verdict.

See where the models agree, where they split and what to verify.

Satcove shows an agreement score and names the disagreements for your own question. Agreement is a signal, so the stakes still decide how much checking is enough.