US adults caring without pay for someone 65 or over, by who they care for: age, work, hours of care, dementia and strain. For testing respite, leave, tax credits and support services.

4 places · 5 traits

Adults who took part in clinical trials at an academic research center, by trial area: age, sex, race and ethnicity, why they joined, travel to the site, how hard the visits were, how well they understood consent, trust in research and whether they would join again. For testing recruitment, payment and trial-design choices.

6 places · 9 traits

Adults in a statewide diabetes registry, by where they get care: type 1 or 2, age, years since diagnosis, treatment, blood sugar control, glucose monitors, cost of care, complications and willingness to share data. For testing programmes, coverage changes and research consent with patients.

4 places · 9 traits

Paid care workers in care homes, home care, live-in care and day care across Germany, France, Italy, the Netherlands, Spain and Poland, by role, citizenship, contract, pay and short staffing. For testing care workforce policies, pay floors, staffing ratios, recruitment from abroad and new home care technology.

6 places · 10 traits

Adult patients of five GP practices in an English primary care network, from a deprived estate to a rural branch surgery, with their long-term conditions, confidence online, how they book and how long they waited. For testing online-first triage, NHS App booking, extended hours, the wider practice team and continuity with a named GP.

5 places · 9 traits

Staff of a regional health system, by site and department: nurses, physicians, aides, therapists, support and office staff, with their shifts, contracts, pay and burnout. For testing staffing, scheduling and workplace policies before taking them to the floor.

10 places · 9 traits

Staff of a made-up NHS acute hospital trust in England, across two hospitals, community services and corporate teams, by staff group, band, contract, nationality, union membership and burnout. For testing pay and strike questions, staffing and agency policy, rotas, international recruitment and digital tools with NHS staff.

4 places · 9 traits

Registered nurses by setting, from hospital floors to home health: age, education, shift, union membership, burnout and plans for the next year. For testing staffing ratios, scheduling, virtual nursing and AI tools.

5 places · 6 traits

Adult patients of a regional hospital system, by kind of visit (emergency, hospital stay, clinic, same-day surgery, childbirth): age, coverage, language, waiting, how well staff explained things, overall rating, the bill and the patient portal. For testing patient-experience changes before surveying real patients.

5 places · 8 traits

Adult patients of a federally funded health center, by site: age, coverage, preferred language, chronic conditions, how they get there and views on video visits. For testing hours, transport, walk-ins, telehealth and language access.

4 places · 6 traits

Adult members of a health plan, by coverage (employer, marketplace, Medicare Advantage, Medicaid): age, income, health, chronic conditions, where they get care, cost barriers and comfort online. For testing benefit, access and outreach changes on patients.

4 places · 8 traits

Practising physicians in the United States, by practice setting (independent, physician group, health system, academic, government): specialty, age, gender, patients a week, main payer, how early they adopt new treatments, whether they see sales representatives, AI tools and burnout. For testing treatments, coverage rules, sales channels and clinical tools on doctors.

5 places · 9 traits