Sources & methodology

Where our claims come from

Every figure and claim in our materials traces to one of three things: published research, a named external dataset, or our own clearly-labelled projections. Here they are, by theme.

These sources validate the science of the field — social prescription and positive psychology — and the market context. They are not evidence of Yu!’s own outcomes, which we measure as we go. Yu! does not diagnose, treat, or cure. Where we project, we say so.

Market & industry

Market size & growth of the digital-wellbeing sector. Grand View Research — Wellness Apps Market (2025). Grand View ↗

The problem: connection is health

U.S. Surgeon General (2023). Our Epidemic of Loneliness and Isolation (Advisory). HHS ↗
Holt-Lunstad (2024). Social connection as a critical factor for mental and physical health. World Psychiatry. DOI ↗
Wang et al. (2023). Social isolation, loneliness and mortality: a meta-analysis of 90 cohort studies. Nature Human Behaviour. DOI ↗
Hotz (2024). The Connection Cure. Simon & Schuster. Book ↗

For the full scientific bibliography — connection, movement, nature, art, service, belonging and flourishing, each verifiable by DOI — see our Science page →

Social prescription in practice

NHS England (2019). The NHS Long Term Plan — social prescribing and the link-worker programme. NHS ↗
Roland, Everington & Marshall (2020). Social prescribing — transforming the relationship between physicians and their patients. New England Journal of Medicine. DOI ↗
Bickerdike et al. (2017). Social prescribing: less rhetoric and more reality. A systematic review. BMJ Open. DOI ↗
USI & IBSA Foundation — “Cultura e Salute” university course (2025), Lugano. A multi-session course on medicine and social prescription, with USI, IBSA Foundation, EOC, the City of Lugano and the LAC. USI ↗

Measurement & frameworks

Topp et al. (2015). The WHO-5 Well-Being Index: a systematic review. Psychotherapy and Psychosomatics. DOI ↗
Avicenna EMA (USC × Harvard) — ecological momentary assessment, the method behind our in-the-moment check-ins. Avicenna ↗
Engel (1977). The need for a new medical model: a challenge for biomedicine (biopsychosocial model). Science. DOI ↗
Seligman — PERMA · Allardt — Having, Loving, Being (HDLB). The wellbeing frameworks our 12 dimensions build on. See Science

Trust & compliance basis

Swiss Federal Act on Data Protection (revised FADP / nFADP, in force 2023). Federal Data Protection and Information Commissioner. FDPIC ↗
EU General Data Protection Regulation — Regulation (EU) 2016/679 (GDPR). EUR-Lex ↗
EU Artificial Intelligence Act — Regulation (EU) 2024/1689. EUR-Lex ↗

Methodology & financials

Financial projections are our own bottom-up model — founder projections, not third-party estimates. Our model
An eight-module bottom-up research base (~250 pages) underpins our market sizing, go-to-market, unit economics and risk assumptions. On request

We checked these ourselves, and it’s a short, honest list — not everything out there. Some links sit behind a publisher paywall or a cookie wall; the reference is what matters. If a source here doesn’t back a claim you’ve seen us make, tell us and we’ll fix it.

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