Two devices measuring the same night and reading 58 and 79 is telling you something — usually that the composite score shouldn't be a single number at all. How cross-source validation handles divergence.
Your primary wearable didn't sync last night. Your dashboard shouldn't just go blank. Source fallback chains degrade gracefully across devices while preserving confidence.
A readiness score with no confidence value is an opinion, not a measurement. How to read credible intervals, spot low-confidence days, and know when to suppress.
Composite health scores fuse many inputs into one number — but only if you know which inputs are trustworthy. Confidence, cross-validation, suppression.
Single metrics lie by omission. A composite score synthesizes HRV, sleep, training load, and recovery into one number — but only if you can see how it's built.