About

The book

Digital Health Metrics is a comprehensive introduction to digital health metric definitions, examples, and reasoning, written for teams building, evaluating, and commissioning digital health products. It runs to 31 topics across 8 parts, available in 53 locales, covering English, Welsh, Simplified Chinese, Spanish, Hindi, Arabic, French, Portuguese, German, Russian, Bengali, Korean, Japanese, Swedish, Dutch, Urdu, Indonesian, Italian, Ukrainian, Finnish, Norwegian, Danish, and Polish — several of these as both an international and a country-specific variant. English is the canonical source; the other locales are AI-translated and have not been reviewed by a fluent speaker. Each topic covers one metric or concept: definition, why it matters, how it's calculated, a worked example, data sources and caveats, pitfalls, and sources.

Pick a language from the home page , then use that locale's contents page for reading order, its A–Z index to look one thing up, or its search.

Benchmark freshness

Many quoted figures refresh regularly — app store benchmarks, clinical evidence thresholds, reimbursement rates, and engagement statistics chief among them. Each topic dates its benchmarks in-line. Re-verify before using any number in a live business case.

This website

This site is a SvelteKit application built with adapter-static, configured per its GitHub Pages guidance: every page is prerendered to plain HTML at build time, so GitHub Pages serves files and nothing else. There is no server, no database, and no tracking.

The book's Markdown is vendored into this repository under content/ rather than referenced across repositories, so the site builds standalone from a fresh clone. pnpm run sync re-copies it from the book. The book's own README is the table of contents: its section headings become the parts of the book, and the order of its links becomes reading order, previous/next, and the sidebar.

Design system

The interface is built from the Lily Design System — its headless Svelte components for structure and accessibility, and its PickerBar helper for the theme, language, text size, and share controls in the header. Headless means the components ship markup, ARIA, and keyboard behaviour but no styling, so the look here comes from a Lily theme plus this site's own stylesheet. All 45 Lily default themes are available from the header. Theme and text size choices persist in this browser.

Licence and source

The book and this site are open source. See the book repository and this site's repository.