Your model benchmark is meaningless without threshold calibration: 0.5 default missed 48 of 156

dbreunig · x · 2026-10-24

dbreunig argues decision-model benchmarks are meaningless unless you adjust cuts and thresholds. The chart shows an email-reply classifier: at the default 0.50 threshold, F1 is 0.774 with 108/156 replies caught, 48 missed, 15 false alarms; calibrating to 0.24 lifts F1 to 0.818, catching 151/156 with only 5 missed at the cost of 62 false alarms. He also calls for reporting F1. A key reminder for eval builders: skewed class distributions make the default 0.5 systematically under-recall.

Related event: DSPy's ReAnchor Boosts Benchmarks as Researcher Warns on Uncalibrated Thresholds(2 posts)→

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