ResearchResearch paperTraining & Scaling · Large Language Models · Reinforcement Learning1 source · Oct 7, 2026

Temporal Predictive Multiplicity: Equally Accurate Time Series Models Yield Different Forecast Trajectories

To address this problem, we introduce temporal predictive multiplicity, a framework that characterizes disagreement over complete forecast trajectories among models with near-identical predictive performance.

Key points

  • Models with near-identical predictive performance can yield substantially different predictions, a phenomenon known as predictive multiplicity.
  • In time-series forecasting, however, predictions across horizons jointly define a trajectory, and horizon-wise comparisons can hide important differences in predictive behavior.
  • We show that constraining predictive performance alone can still admit a broad range of different trajectories.
  • Our framework, therefore, exposes a gap in existing multiplicity studies: models with indistinguishable predictive performance imply fundamentally different temporal trajectories, with consequential downstream effects.

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