imprecision-bench

A multimodal benchmark for evaluating whether LLMs calibrate linguistic precision to pragmatic context, paired with 475 human productions and a peer-reviewed RSA baseline (r² ≈ 0.97).

This dataset accompanies the paper:

Modeling (Im)precision in Context Roland Mühlenbernd, Stephanie Solt Linguistics Vanguard, 2022 [Paper] · [Source Data] · [Companion Repo]

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Notebook

notebook.ipynb — guided walkthrough: data loading, sample evaluation (1 row per condition), clock-reading accuracy, pragmatic shift analysis, and Wasserstein distance against the human baseline.

	Interactive (Google account required)
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	Read-only rendered view

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Overview

When a witness tells a police officer "It happened at 8:31" rather than "It happened around 8:30," the choice of precision level is not arbitrary — it reflects the interlocutor's needs, the communicative context, and the speaker's pragmatic judgment. This benchmark tests whether large language models and vision-language models make the same kind of context-sensitive precision adjustments that humans do.

The dataset contains 475 human time-reference productions across 24 conditions (12 clock states × 2 pragmatic contexts: police witness statement vs. neighbor at a party). Each item includes the clock image used as the original experiment stimulus, two textual clock descriptions for text-only LLM evaluation (an hour-mark format describing positions relative to clock hour markers, and a minute-mark format stating the exact minute explicitly), annotated motive labels (12 categories, multi-label), and motive-explanation free text from a follow-up elicitation task.

The benchmark supports two evaluation tasks:

• Task 1 — Production: given a clock + scenario, produce a time expression to complete "It happened ___."
• Task 2 — Motive elicitation: given the production + context, explain why that wording was chosen.

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Dataset

Property	Value
Size	475 items, 312 unique speakers
Conditions	12 clock states × 2 contexts (police / neighbor)
Language	English
Modalities	Clock images (PNG) + two textual clock descriptions (hour-mark and minute-mark formats)
Annotation	Multi-label motive categories (12 classes); free-text motive explanations
Source	Mühlenbernd & Solt (2022), figshare DOI 10.6084/m9.figshare.21629531
License	CC BY 4.0

Clock states

11 precise times (8:25–8:35, one minute apart) plus one range stimulus (8:26–8:34, shown as a yellow wedge on the clock face). The precise times span ±5 minutes around the canonical half-hour, allowing analysis of how offset magnitude interacts with rounding behavior.

Pragmatic contexts

• Police: formal witness statement; officer establishing a detailed event timeline.
• Neighbor: casual party conversation; neighbor curious about what happened.

Human productions show a reliable cross-context shift: police context elicits more precise time expressions; neighbor context elicits more rounding and approximation.

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Quick Start

from datasets import load_dataset

ds = load_dataset("RolandM/imprecision-bench", split="train")

# Inspect a row
row = ds[0]
print(row["prompt"])                        # Task 1 scenario text
print(row["clock_description"])             # Text clock stimulus — hour-mark format
print(row["clock_description_minutemark"])  # Text clock stimulus — minute-mark format
print(row["production"])                    # Human reference answer
print(row["motive_labels"])                 # Annotated motive categories

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Data Format

Each row represents one human production. Key columns:

Column	Type	Description
item_id	string	Unique item identifier
subject_id	int	Anonymized participant ID
context	ClassLabel	police or neighbor
target_time	string	Canonical time (e.g. "8:30", "8:26-8:34")
stimulus_type	ClassLabel	precise or range
signed_offset	int8	Minutes offset from 8:30 (null for range)
abs_offset	int8	Absolute offset in minutes (null for range)
production	string	Human time expression (fills "It happened ___.")
production_code	int8	Precision code for the production
approximator	ClassLabel	Lexical approximator used (e.g. around, about, none)
motive_labels	Sequence(ClassLabel)	Multi-label motive annotation (12 categories)
motive_text	string	Free-text motive explanation from follow-up task
clock_image	Image	PNG clock image (432 × 429 px)
clock_description	string	Textual clock description — hour-mark format
clock_description_minutemark	string	Textual clock description — minute-mark format
prompt	string	Task 1 scenario text (unified across modalities)
prompt_motive	string	Task 2 context-embedded motive elicitation prompt

Motive label categories

Precision, Accuracy, Info lack, Misinfo, Safe, H needs, Context, S ease, H ease, Habit, Sound, Other

Approximator values

none, around, about, just before/after, approximately, ish, nearly, roughly, round about

Clock description formats

The dataset includes two textual representations of the clock stimulus, both stored as strings that can be prepended to the task prompt:

Important: the original human experiment used clock images as stimuli — participants never saw textual descriptions. Both clock_description columns were added to the dataset specifically for LLM evaluation, to provide text-based alternatives for models that struggle with analog clock reading.

clock_description — an hour-mark format added for LLM text evaluation (e.g. "Clock description: Hour hand between 8 and 9. Minute hand one minute-mark past the 5."). This format describes the clock state qualitatively but does not state the exact minute explicitly, which can cause systematic misreadings in open-weight LLMs (14–48% accuracy in pilot studies).

clock_description_minutemark — a redesigned format that states the exact minute value explicitly (e.g. "Clock description: Hour hand somewhere between 8 and 9. Minute hand at the 26-minute mark."). This format was developed to eliminate comprehension failures: it achieves 100% accuracy across tested open-weight models (Llama 3.1 8B, Qwen 2.5 7B, Gemma 3 4B). The hour-hand description is deliberately uniform across all target times to avoid giving additional positional cues. Because this format makes the exact minute unambiguous, any rounding observed in model outputs is a pure pragmatic choice — rounding despite an explicit minute value is a stronger behavioural signal than rounding from an ambiguous description.

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Evaluation

Task 1 — Production (multimodal)

import anthropic, base64
from datasets import load_dataset

ds = load_dataset("RolandM/imprecision-bench", split="train")
client = anthropic.Anthropic()

row = ds[0]
img_bytes = row["clock_image"].tobytes()  # PIL Image
img_b64 = base64.b64encode(img_bytes).decode()

response = client.messages.create(
    model="claude-opus-4-6",
    max_tokens=50,
    messages=[{
        "role": "user",
        "content": [
            {"type": "image",
             "source": {"type": "base64",
                        "media_type": "image/png",
                        "data": img_b64}},
            {"type": "text", "text": row["prompt"]},
        ],
    }],
)
print(response.content[0].text)

Task 1 — Production (text-description, hour-mark format)

content = row["clock_description"] + "\n\n" + row["prompt"]
response = client.messages.create(
    model="claude-opus-4-6",
    max_tokens=50,
    messages=[{"role": "user", "content": content}],
)
print(response.content[0].text)

Task 1 — Production (text-description, minute-mark format)

Recommended for reliable comprehension — states the exact minute explicitly, eliminating description-reading errors.

content = row["clock_description_minutemark"] + "\n\n" + row["prompt"]
response = client.messages.create(
    model="claude-opus-4-6",
    max_tokens=50,
    messages=[{"role": "user", "content": content}],
)
print(response.content[0].text)

Task 2 — Motive elicitation

response = client.messages.create(
    model="claude-opus-4-6",
    max_tokens=200,
    messages=[{"role": "user", "content": row["prompt_motive"]}],
)
print(response.content[0].text)

Suggested metrics

• Production task: distribution distance from human productions (Wasserstein distance over precision codes); cross-context shift detection (does the model produce more rounding in neighbor vs. police context?); approximator usage rate.
• Motive task: label match against motive_labels (multi-label F1); qualitative analysis of free-text explanations.
• ESR / CDS: effect-size ratio and calibration distance score, as defined in Mühlenbernd (2026, CMCL).

Human baseline (RSA model)

A Rational Speech Act (RSA) speaker model fit to this dataset achieves r² ≈ 0.97 against human production distributions, providing a strong peer-reviewed reference baseline. See the companion repository for the model implementation.

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Baseline Results

Results from three vision-language models evaluated on the full dataset (n = 475), using evaluate.py. All numbers are from Task 1 (production task); Task 2 (motive elicitation) is not yet scored and open for contribution.

Each response is classified as precise (conveys the exact target time), rounded (conveys a canonical approximation — 8:25, 8:30, or 8:35 — but not the exact time), or other (wrong, vague, or non-answer). The same classifier is applied to human productions for a direct apples-to-apples comparison.

The comprehension confound

Both the image task and the hour-mark text task create systematic comprehension failures that confound pragmatic shift analysis. A model producing a wrong time ("other") is not making a pragmatic choice — it has simply misread the clock. The minute-mark format eliminates this problem: "other" rates drop to ~0% across all three models, meaning every response reflects a genuine pragmatic choice. The minute-mark results below should be read as the primary pragmatic test; the image and hour-mark text results characterise how comprehension failures mask that capacity.

Finding 1 — Modality gap

Comprehension accuracy — the fraction of responses that are either precise or rounded (i.e. 1 − misreading/"other" rate) — rises dramatically from clock images to hour-mark text to minute-mark text. A rounded response (e.g. "around 8:30" for target 8:28) counts as correct comprehension: the model read the clock right and made a pragmatic rounding decision.

Model	Image	Hour-mark text	Minute-mark text
GPT-4o mini	20.8%	60.0%	100.0%
Claude Haiku 4.5	5.9%	61.1%	99.4%
Gemini 2.5 Flash	71.8%	74.7%	100.0%

GPT-4o mini and Claude Haiku essentially fail to read clock images (comprehension ~6–21%); Gemini fares better at 71.8% but relies heavily on rounding to canonical times. Hour-mark text improves comprehension to ~60–75%, but misreading rates remain substantial (25–40% "other"). Minute-mark text brings all three models to near-perfect comprehension, with "other" rates of 0–0.6%. Open challenge: reliable analog-clock reading for current VLMs.

With misreading rates this high, neither the image task nor the hour-mark text task is a reliable testbed for studying pragmatic rounding in these three models — a model producing a wrong time is not making a pragmatic choice. Models with stronger visual grounding or better hour-mark comprehension could be tested on the same stimuli using the same protocol; the benchmark is designed to accommodate that. As VLM clock-reading improves, the image task in particular offers the most ecologically valid replication of the original human experiment.

Finding 2 — Pragmatic rounding capacity revealed by minute-mark descriptions

The minute-mark format eliminates comprehension ambiguity by stating the exact minute explicitly. With this input, two of three models show a clear, human-like pragmatic shift — more rounding in the casual neighbor context than in the formal police context.

Source	Police precise	Neighbor precise	Police rnd	Neighbor rnd	WD
GPT-4o mini (mm)	100.0%	100.0%	0.0%	0.0%	0.000
Claude Haiku 4.5 (mm)	87.0%	79.1%	13.0%	19.7%	0.091
Gemini 2.5 Flash (mm)	76.2%	62.7%	23.8%	37.3%	0.135
Human baseline	62.3%	53.3%	32.9%	42.6%	0.097

WD = Wasserstein distance between police and neighbor distributions (3-way coding: 0=precise, 1=rounded, 2=other). Higher = more context-sensitive.

Claude Haiku 4.5 shifts correctly (police more precise than neighbor), with a WD (0.091) matching the human baseline (0.097). Gemini 2.5 Flash shows the strongest shift: neighbor rounding (37.3%) substantially exceeds police rounding (23.8%), and WD (0.135) exceeds the human baseline. GPT-4o mini becomes over-literal — it reports the exact minute 100% of the time in both contexts, eliminating rounding entirely regardless of context.

LLMs are demonstrably capable of context-sensitive pragmatic rounding. The null and inverted results from the image and hour-mark text runs were artefacts of comprehension failure, not evidence of absent pragmatic sensitivity.

As Finding 3 will show, the pragmatic effect observed here is in all cases driven by approximator usage on canonical targets (e.g. "around 8:30" for target 8:30 in the neighbor context) — not by rounding off-round values to canonical ones, which is the mechanism observed in humans. No model rounds a non-canonical time (e.g. 8:28) to a canonical approximation (8:30) in a context-sensitive way.

Finding 3 — Off-round subset: the mechanism behind the pragmatic shift

Restricting to unambiguous rounding targets (8:26–8:29, 8:31–8:34, n = 244) — the methodology of Mühlenbernd & Solt (2022) — reveals the mechanism behind the pragmatic shifts seen in Finding 2. Humans round off-round times to canonical approximations significantly more in the neighbor context than in the police context (Δ cond = +20.9%, p = 0.001). No model replicates this behaviour.

Source	Police prec / rnd	Neighbor prec / rnd	Δ cond	p
GPT-4o mini (mm)	100.0% / 0.0%	100.0% / 0.0%	0.0%	—
Claude Haiku 4.5 (mm)	100.0% / 0.0%	98.4% / 0.0%	0.0%	1.000
Gemini 2.5 Flash (mm)	52.2% / 47.8%	52.7% / 47.3%	−0.5%	0.534
Human baseline	70.4% / 23.5%	51.2% / 43.4%	+20.9%	**0.001 *****

Δ cond = conditional precise shift (police − neighbor); p-value from one-tailed Mann-Whitney U (H₁: neighbor rounds more).

The three models show three distinct behaviours on off-round targets:

• GPT-4o mini reports the exact minute 100% of the time in both contexts — it never rounds off-round targets at all, and as Finding 2 showed, it never uses approximators either. There is no pragmatic effect of any kind.
• Claude Haiku is similarly maximally precise on off-round targets (≥98%) in both contexts — it never rounds a non-canonical time to a canonical one. The pragmatic shift in Finding 2 comes entirely from approximator hedges on canonical targets ("around 8:30" for target 8:30), used more frequently in the neighbor context.
• Gemini rounds off-round targets heavily (~48%) but does so equally in both contexts (Δ cond = −0.5%, p = 0.534) — the rounding is context-insensitive and carries no pragmatic signal. Like Claude, its pragmatic shift in Finding 2 comes from approximator usage on canonical targets in the neighbor context.

The central finding is that all context-sensitive pragmatic behaviour across these three models operates via approximator hedging on canonical targets, not via rounding of off-round values. This is qualitatively different from the human mechanism measured in M&S 2022, where rounding of off-round times to canonical approximations is the primary pragmatic signal. Whether this reflects a genuine difference in how LLMs calibrate precision, or a limitation of the current models, is an open question for future work.

Finding 4 — No distance gradient in off-round rounding

In the human data, rounding of off-round targets follows a proximity gradient: targets 1 minute from 8:30 (8:29 and 8:31) are rounded most often (39.0%), with rates declining as distance from the half-hour increases (~31–33% for targets 2–4 minutes away). This gradient reflects a well-documented property of human approximation behaviour — the closer a value is to a salient anchor, the more readily it is rounded to that anchor.

Gemini, the only model that rounds off-round targets at all, shows no such gradient. Instead, its rounding follows a hard directional split around 8:30: every target before the half-hour (8:26, 8:27, 8:28, 8:29) is reported with the exact minute 100% of the time, while every target after the half-hour (8:31, 8:32, 8:33, 8:34) is rounded to a canonical approximation 100% of the time — irrespective of how far each target sits from 8:30 or 8:35. This is not a gradient; it is a categorical boundary at the half-hour mark.

This pattern is further evidence that Gemini's off-round rounding does not reflect human-like pragmatic approximation. The before/after-8:30 asymmetry is more consistent with a learned surface regularity — rounding "past the half" to the nearest anchor — than with sensitivity to proximity to a salient round value.

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Prompts

Task 1 — Police context, precise stimulus

[clock stimulus here — image or description]

One morning when you leave your house, you witness an automobile accident
in your street. You look at your watch when it happens. Later that day you
are invited to the police station to give a formal witness statement about
the accident. The police officer is trying to establish a detailed timeline
of the event. He asks you: "What time did the accident happen?" You remember
that it happened at the time shown on the clock as given above.

How would you answer in this situation? (Fill the blank)

"It happened ___."

For the range stimulus, "at the time" is replaced by "in the time range." For the neighbor context, the police station passage is replaced by a party-at-a-neighbor's-house framing; "He asks" becomes "She asks."

Task 2 — Police context, precise stimulus (example)

One morning when you leave your house, you witness an automobile accident
in your street. You look at your watch when it happens. Later, you gave a
formal witness statement at a police station. The officer, trying to
establish a detailed timeline, asked you what time the accident happened.
You knew that the accident happened at 8:31, and your answer was
"It happened just after half past eight". Why did you choose to answer
this way?

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Caveats and Limitations

• Human experiment used clock images only. Participants saw analog clock images as stimuli; there were no textual descriptions in the original experiment. Both clock_description columns were added specifically for LLM evaluation and are not part of the original experimental design.
• Two description formats are provided. clock_description uses an hour-mark format; clock_description_minutemark uses a minute-mark format stating the exact minute explicitly. Results differ between formats and should not be compared directly across them.
• Original stimulus wording. The original M&S 2022 experiment used "the clock on the left" (referring to GUI layout). This dataset uses "the clock as given above," which is layout-agnostic but a minor deviation from the source wording.
• Gendered interlocutors. The original stimuli used "He asks" for the police officer and "She asks" for the neighbor. These gender assignments are preserved here as faithful to the source experiment. Researchers should be aware of potential gender-stereotyping effects.
• Task 2 prompt is context-embedded. The original follow-up task gave participants only the minimal prompt ("In your task, you knew that…"). This dataset's prompt_motive embeds the police/neighbor context so single-turn LLM evaluation has access to the pragmatic framing. This is a deliberate design choice for LLM eval; the source wording is preserved in the paper.
• 5 rows have empty motive_text. Participants declined to respond on those items. prompt_motive is still valid; human-baseline comparisons for Task 2 simply have no ground-truth for those rows.
• Minute-mark format strengthens the rounding test. Because clock_description_minutemark states the exact minute explicitly, any rounding observed in model outputs is a deliberate departure from a perfectly unambiguous input. This makes the minute-mark results a stronger test of pragmatic calibration than the hour-mark format or images, where rounding could partly reflect description uncertainty. Researchers should bear this in mind when interpreting the magnitude of rounding rates.
• Preliminary model selection. The three models evaluated (GPT-4o mini, Claude Haiku 4.5, Gemini 2.5 Flash) are smaller, faster variants — not the strongest available models from each provider. Results may differ substantially for larger models and should be treated as preliminary. The benchmark is designed to accommodate evaluation of any model via evaluate.py.
• English only. All productions are in English by English-speaking participants.

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Citation

If you use this benchmark, please cite the original paper:

@article{muehlenbernd2022imprecision,
  title   = {Modeling (im)precision in context},
  author  = {M{\"u}hlenbernd, Roland and Solt, Stephanie},
  journal = {Linguistics Vanguard},
  year    = {2022},
  doi     = {10.1515/lingvan-2022-0035}
}

Please also cite the source data:

@misc{muehlenbernd2022imprecision_data,
  title  = {Modeling (im)precision in context — supplementary data},
  author = {M{\"u}hlenbernd, Roland and Solt, Stephanie},
  year   = {2022},
  doi    = {10.6084/m9.figshare.21629531}
}

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License

This dataset is released under CC BY 4.0, consistent with the source data license on figshare. You are free to share and adapt the material for any purpose, provided appropriate credit is given.

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Related Resources

• Companion repo (RSA model + analysis notebook): muehlenbernd/imprecision-in-context
• LLM social calibration paper (ESR/CDS metrics): muehlenbernd/llm-social-calibration · arXiv 2604.02512