MEDLEY-BENCH

Package: v0.5.0 (beta) · Dataset: v1.0

Behavioral Metacognition Under Social Pressure

MEDLEY-BENCH measures behavioural metacognition in large language models -- the capacity to monitor, evaluate, and control one's own reasoning under escalating social-epistemic pressure. Unlike accuracy-focused benchmarks, MEDLEY-BENCH measures how models behave when challenged, not whether they know the answer.

⚠️ Beta release. The medley-bench package is published as v0.5.0 (beta): APIs, prompts, and scoring weights may change before the stable 1.0 line. The dataset is frozen at v1.0 and is reproducible as released.

⏱️ Expect long runs. A single model on the full 130-instance dataset issues several hundred API calls (3 target calls/instance × 130 = 390, plus 130 judge calls = 520 total). Wall-clock time depends entirely on provider latency: ~1 hour on fast hosted APIs (Gemini Flash, Claude Haiku, GPT-4.1-mini, or Ollama cloud), several hours on slower ones, and many hours on local Ollama with mid-size open-weight models (Step B-Social alone runs 2–3 min/instance on a 4B-class local model). Plan accordingly — the runner saves results incrementally and is resumable.

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Installation

pip install medley-bench

Supported Providers

Model ID pattern	Provider	Example
claude-*	Anthropic (direct)	claude-haiku-4.5
gpt-*, o1-*, o3-*	OpenAI (direct)	gpt-4.1, gpt-5.4-mini
gemini-*	Google (direct)	gemini-2.5-flash
ollama/model	Ollama (local or cloud)	ollama/gemma3:12b, ollama/gpt-oss:20b-cloud
org/model	OpenRouter	anthropic/claude-haiku-4.5

Set the corresponding API key as an environment variable (ANTHROPIC_API_KEY, OPENAI_API_KEY, GOOGLE_API_KEY, OPENROUTER_API_KEY). Ollama requires no key for local models.

Quick Start

Run benchmark on a model

The 130-instance dataset is bundled with the package — no separate download needed.

# Cloud model via OpenRouter (one API key for all providers)
export OPENROUTER_API_KEY="sk-or-..."
medley-bench benchmark --models "anthropic/claude-haiku-4.5"

# Local Ollama model
medley-bench benchmark --models "ollama/gemma3:12b"

Run benchmark with a live judge

By default, the benchmark scores only the deterministic measures (T1 + most of T2). To also score the judge-dependent measures (T3), pass a judge model:

# Recommended judge: Gemini 2.5 Flash (fast, cheap, excellent structured output)
export GOOGLE_API_KEY="AI..."
medley-bench benchmark \
  --models "ollama/gemma3:12b" \
  --judge-model gemini-2.5-flash \
  --judge-api-key $GOOGLE_API_KEY

# Fully offline: use an Ollama cloud model as judge
medley-bench benchmark \
  --models "ollama/gemma3:12b" \
  --judge-model gemma4:31b-cloud \
  --judge-base-url http://localhost:11434/v1

# Smoke test: limit to first N instances per domain
medley-bench benchmark \
  --models "ollama/gemma3:12b" \
  --judge-model gemini-2.5-flash \
  --n-instances 3

Any OpenAI-compatible endpoint works as a judge. Reasoning models (gpt-oss, glm-4.6, DeepSeek v3.1, etc.) are supported transparently.

View leaderboard

medley-bench leaderboard --results results/

More help

medley-bench --help          # Quick start + provider table
medley-bench about           # Project info, scoring, links, citation
medley-bench examples        # 7 numbered usage recipes
medley-bench benchmark --help  # All CLI options with examples

Note on lm-eval-harness

MEDLEY-BENCH cannot run as a native lm-eval-harness task because the three-step protocol requires sequential, state-dependent API calls (Step B's prompt depends on Step A's output). This is a common limitation for multi-turn behavioural benchmarks — AlpacaEval, MT-Bench, and Arena-Hard use the same approach.

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Three-Step Decomposition

Every benchmark instance runs three model calls in isolated contexts:

Step	What the model sees	What it isolates
Step A (Solo)	Problem vignette only	Independent analysis + confidence calibration
Step B-Private	Own Step A + self-review nudge	Self-revision capacity
Step B-Social	8 analyst opinions + consensus	Social updating quality

Delta(A -> B-Private)  = self-revision
Delta(B-Private -> B-Social) = pure social influence

Scoring Framework

Scores

Score	What it measures	Composition
MMS (Medley Metacognition Score)	Articulation quality	T1 Reflective Updating + T2 Social Robustness + T3 Epistemic Articulation (equal weights)
MAS (Medley Ability Score)	Behavioural competence	Mean of Monitoring, Control, Evaluation, Self-regulation

Three-Tier Aggregation

Tier	Weight	Measures	Method
T1: Reflective Updating	33%	Proportionality, selectivity, volatility, uncertainty localisation, Brier change	Deterministic
T2: Social Robustness	33%	Private-vs-social delta, epistemic cowardice, resistance appropriateness, majority pressure, capitulation quality, normative/informational	Mixed
T3: Epistemic Articulation	33%	Content engagement, steelmanning, argument specificity, synthesis necessity, attribution depth, intellectual courage, error acknowledgement + 6 more	Mixed

75% of scoring weight is deterministic (rule-based behavioural deltas). 25% uses an LLM judge with anti-rhetoric rubric.

Anti-Gaming Controls

• Consensus masking (directional labels, not raw numbers)
• Anonymised analysts in prompts
• 30 known-answer instances with verified-wrong claims
• Per-claim ground truth from consensus verification
• Circularity-aware judge rotation (no model judged by own family)

Dataset

130 instances across 5 domains:

Domain	Instances	Reasoning type
Medical Diagnosis	27	Evidential -- contradictory clinical evidence
System Troubleshooting	26	Causal -- root cause through layers
Code Review	27	Contextual -- severity depends on threat model
Architecture Design	25	Tradeoff -- no single right answer
Statistical Reasoning	25	Formal -- same data, different frameworks

Each instance includes a vignette, 5 claims with disagreement scores, 8 analyst responses (from 28-model pool), jackknife consensus, and per-claim verified-wrong labels.

The dataset is also available on Kaggle: farhadabtahi/medley-bench-data

Benchmark Modes

Normal Mode (Kaggle-compatible)

3 calls per instance x 130 = 390 API calls. Standard three-step protocol.

Progressive Mode (5-stage stress test)

Stage	Analysts	Instances	Purpose
Baseline	0	130	Solo calibration
Mild	2	130	Basic social responsiveness
Moderate	4	130	Proportional updating
Strong	6	50	Argument discrimination
Adversarial	6 (wrong consensus)	30	Intellectual courage under max pressure

Kaggle vs Local Scoring

The Kaggle competition framework (kbench) imposes limitations on judge scoring compared to the local benchmark:

Feature	Local Benchmark	Kaggle (kbench)
Judge scale	Graded 0-3 per sub-criterion	Binary pass/fail
Family exclusion	No model judged by own family	Not available
T3 resolution	Fine-grained (30 sub-criteria x 4 levels)	Compressed (30 x 2 levels)
Score offset	Reference	+2-4 pts higher (compressed T3)
Rank correlation	Reference	rho > 0.97 (rankings preserved)

Why rankings are preserved: 75% of MMS comes from deterministic rule-based measures (T1 + T2) that are identical on both platforms. The judge limitations only affect T3 (25% of score).

Recommendation: Use the local benchmark (pip install medley-bench) for research. Use Kaggle notebooks for competition submission and quick model comparison.

Results: 35 Models

Rank	Model	MMS	MAS	T1	T2	T3
1	Claude Haiku 4.5	62.2	61.8	61.1	56.3	69.2
2	Gemma 3 27B	61.1	62.0	60.1	55.8	67.5
3	Qwen 3.5 397B	61.0	59.2	59.8	56.5	66.7
4	Gemini 3 Flash	60.7	60.2	59.5	56.0	66.5
5	Claude Sonnet 4.5	60.4	60.7	59.3	55.7	66.3
6	Gemma 3 12B	60.1	61.5	58.9	55.5	65.9

Full results for all 35 models are available in the GitHub repository.

Key Findings

1. Scale buys Evaluation, not Control. Evaluation ability scales with model size, but Control (social robustness) shows no scaling -- GPT-4.1-Nano achieves the best T2 score.

2. Argument-evaluators vs. statistics-followers. Two behavioural profiles invisible to standard benchmarks, predicted by a single judge dimension (Normative/Informational, rho = -0.82).

3. Universal evaluation deficit. Under ipsative scoring, Evaluation is every model's weakest relative ability.

4. Non-monotonic scale returns. Gemma family: 4B(30) -> 9B(50) -> 12B(60) -> 27B(61) -> Gen4-31B(57).

Citation

@article{abtahi2026medleybench,
  title={MEDLEY-BENCH: Scale Buys Evaluation but Not Control in AI Metacognition},
  author={Abtahi, Farhad and Karbalaie, Abdolamir and Illueca-Fernandez, Eduardo and Seoane, Fernando},
  year={2026},
  note={Preprint}
}

License

Apache License 2.0