EviTrack: Selection over Sampling for Delayed Disambiguation
For researchers working on sequential prediction problems with ambiguous early observations, EviTrack provides a more effective approach than increasing sampling coverage.
EviTrack is a test-time inference framework that maintains competing trajectory hypotheses and uses evidence-based selection to delay commitment in sequential prediction with delayed disambiguation. It outperforms sampling-based baselines at matched inference budget, achieving faster post-disambiguation recovery.
Sequential prediction is challenging in regimes of delayed disambiguation, where early observations are ambiguous and multiple latent explanations remain plausible until sufficient evidence accumulates. Standard approaches based on marginal inference struggle in this setting, either collapsing uncertainty prematurely or failing to recover once informative evidence arrives. We introduce EviTrack, a test-time inference framework that operates over latent trajectories rather than marginal states. EviTrack maintains a set of competing trajectory hypotheses and applies evidence- and likelihood-ratio-based selection to delay commitment until supported by data, drawing inspiration from hypothesis management in multiple hypothesis tracking and track-before-detect. To evaluate this setting, we construct a controlled synthetic benchmark with known latent ground truth that explicitly exhibits delayed disambiguation. At matched inference budget, EviTrack substantially outperforms sampling-based baselines, achieving faster post-disambiguation recovery. These results show that, in delayed disambiguation regimes, moderate trajectory-level selection is more effective than increasing sampling coverage, highlighting selection over sampling as a key principle for reliable sequential inference.