On the Entropy Calibration of Language Models

Percy Liang (Stanford University) · Steven Cao (Stanford University) · Gregory Valiant (Stanford University)
autoregressive modelsblack box modeldataset sizedistribution truncationempirical measuremententropy calibrationerror accumulationlanguage modellog lossmiscalibrationpower law exponentpredictive modelingscaling behaviorscaling exponentstext qualitytheoretical setting

We study the problem of entropy calibration, which asks whether a language model's entropy over generations matches its log loss on human text. Past work found that models are miscalibrated, with entropy per step increasing (and text quality decreasing) as generations grow longer. This error accumulation is a fundamental problem in autoregressive models, and the standard solution is to truncate the distribution, which improves text quality at the cost of diversity. In this paper, we ask: is miscalibration likely to improve with scale, and is it theoretically possible to calibrate without tradeoffs? To build intuition, we first study a simplified theoretical setting to characterize the scaling behavior of miscalibration with respect to dataset size. We find that the scaling behavior depends on the power law exponent of the data distribution