> ## Documentation Index > Fetch the complete documentation index at: https://docs.elata.bio/llms.txt > Use this file to discover all available pages before exploring further. # Metrics and Scores > How Elata turns signals into features and scores, why scores withhold themselves, and how the biometric Score is built. There are two different things in this area, with different statuses: | | What it is | Status | | - | - | - | | **SDK headline scores** | Open-source score formulas in `biosignal-analytics` that builders can run on their own data | Experimental (source only, not on npm) | | **The biometric Score on Elata** | One cross-app Score per user, built from derived results apps report with consent | Live | *** ## From signals to features Before any score, the SDK computes **features**: well-defined, reproducible numbers. * **EEG window features:** band powers (absolute, relative, log), spectral entropy, dominant frequency, alpha peak, Hjorth parameters, and quality flags * **Pulse features:** heart rate, RMSSD, SDNN, and signal quality * **Robust statistics:** medians and median absolute deviations instead of means, so one bad sample doesn't skew the result * **Personal baselines:** a rolling 30-day median and range for each person, with outlier rejection *** ## SDK headline scores Experimental. `biosignal-analytics` is available as source code and may change before its first npm release. | Score | Describes | | - | - | | **Measurement Quality** | The recording, not the person. Always available alongside any other score. | | **Activation** | How far physiological arousal moved from the person's baseline | | **Recovery** | How well arousal came back down after an activation | | **Focus** | Engagement during a task | | **Readiness** | Day-to-day state against the personal baseline | | **Resilience** | How consistently someone recovers over time | These are **product interpretations, never measurements**, and the SDK says so. Two design rules keep them honest: 1. **Every contributor is visible.** Each score exposes its inputs with their weights, standardized values, and quality. 2. **Scores withhold themselves.** Instead of guessing, a score returns no value plus a reason when it can't be computed responsibly: | Reason | Meaning | | - | - | | Inputs missing | The measurement wasn't made | | Insufficient quality | It was made too poorly to read | | Insufficient baseline | There's no usable personal baseline to compare with | | No task context | Focus: nothing was being attended to | | Insufficient history | Readiness needs 14 qualified days; Resilience needs 21 days plus 6 recovered activations | A missing input never silently becomes a neutral middle value. *** ## The biometric Score on Elata The Score is a single number from 0 to 100 that reflects a user's results across all the apps they use, **only if they opt in**. How it's built: * **Apps report derived session results, never raw signal.** A report says, for example, that the user's calm level went from 0.42 at baseline to 0.61 during a five-minute session, with its signal quality and confidence. * **Improvement relative to the user's own baseline matters**, not absolute values that differ between people. * **Low-quality sessions are dropped**, and the Score shows as "calibrating" until there are enough good sessions to be stable. * **Consent is checked on the server** for every report, so an app can't contribute without it. * **Only approved apps can contribute.** An app needs a permission granted by Elata before its reports count. See [Privacy and consent](/overview/privacy-and-consent) and, for builders, [Consent and insights](/apps/platform/consent-and-insights). *** ## Sources * [`biosignal-analytics` README](https://github.com/Elata-Biosciences/elata-bio-sdk/tree/main/packages/biosignal-analytics) (public SDK repository) * [Metrics and scores](/apps/platform/metrics-and-scores) (builder docs) This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.