A resting heart rate of 68 is normal in the population and elevated for you. Personalized thresholds built from your own p25/p50/p75 catch meaningful shifts that population norms miss entirely.
Consumer EEG is noisy. Muscle activity, blink, jaw clench, and electrode liftoff produce spectral signatures that drown the real brain signal. How autoencoder-based artifact detection separates brain from noise.
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.
Composite health scores fuse many inputs into one number — but only if you know which inputs are trustworthy. Confidence, cross-validation, suppression.