The 2025 National Health Survey (INS) aligns with the European EHIS project and is regulated by EU directives, ensuring data harmonization and international comparability. National questions, such as life satisfaction, were developed in collaboration with the National Institute of Health Doutor Ricardo Jorge.
Doubts regarding the validity of the results have been addressed through a fact-check detailing the methodology. The sample, comprising 22,000 households (2,520 in Madeira), is stratified and multi-stage. In each randomly selected dwelling, one resident aged 15 or older, whose birthday was most recent, is invited to participate.
Interviews were conducted in person, by phone, and online between September and December 2025, with a valid response rate of 68.6%. Results are weighted by region, age, sex, education, and household size, based on population estimates. Methodological limitations, such as not disclosing estimates with a coefficient of variation exceeding 20%, are acknowledged by INE.
Life satisfaction is measured using Diener's scale (1985), a standardized instrument with five questions and responses on a scale of 1 to 7, ensuring a consistent method for all assessments.
