Confidence Comes from Experience: Experiential Confidence Estimation from Reasoning to Agents
XConf estimates LLM confidence from accumulated past episodes, improving calibration and discrimination across nine benchmarks at one-tenth self-consistency cost.
Researchers propose XConf, an experiential confidence estimator that augments current inference with a stored record of the model's graded past episodes, including reflections, stated confidence, outcomes, and lessons. A Recall stage retrieves episodes from similar tasks with similar stated confidence and reads off historical success rates, while a Reflect stage prompts the model to name recurring failure modes and restate confidence. Across nine benchmarks in reasoning, coding, multimodal QA, and interactive agents, and four models from three families, XConf beats or matches ten-sample self-consistency in AUROC on 23 of 24 comparisons with much lower ECE, at a tenth of the generation cost. For selective prediction, abstaining on the 10% least-confident episodes raises delivered success rate by up to 8.7 points on agent tasks.
- Stores graded past episodes with reflections, stated confidence, outcomes, and lessons for retrieval.
- Recall stage reads historical success rates for similar tasks and confidence levels.
- Beats or matches ten-sample self-consistency AUROC on 23 of 24 comparisons at one-tenth the cost.
- Requires no logit access or weight updates; abstention lifts agent success up to 8.7 points.
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Reliable confidence estimation is increasingly central to the trustworthy deployment of language models: a calibrated estimate of the probability that an output is correct decides what to ship, what to escalate, and what to retry. Existing confidence estimators, however, share one design premise: they only read the current inference process, either by introspecting on it, scoring its token probabilities, or resampling it. We argue that the current inference is not a sufficient basis for confidence. We propose XConf (eXperiential Confidence): estimating confidence together with the model's accumulated experience. The experience is stored as a record of the model's own graded past episodes, each holding the task, the model's reflection, its stated confidence, the outcome, and a lesson written once the grade arrived. Given a new task, XConf's Recall stage retrieves past episodes on similar tasks met with a similar stated confidence, and reads off their historical success rate; its Reflect stage shows the model this record, has it name its recurring failure mode, and restate a confidence now informed by its own track records. Our estimator is format-general, requiring no logit access or weight updates, and costs only one answer generation. Across nine benchmarks spanning reasoning, coding, multimodal QA, and interactive agents, and four models from three families, XConf beats or matches ten-sample self-consistency in discrimination (AUROC) on 23 of 24 comparisons, with much lower calibration error (ECE), at a tenth of the generation cost. Used for selective prediction, abstaining on the 10% least-confident episodes raises the delivered success rate by up to 8.7 points on agent tasks. We therefore see experiential confidence estimation as a new paradigm for future general-purpose confidence estimation.
Text extracted automatically; images, tables and formatting may be missing. Original: https://huggingface.co/papers/2609.17708