The data presented in the Global Health Workforce Statistics database are processed data extracts of the national reporting in the NHWA data platform. Complementing the national reporting, additional sources such as the National Census, Labour Force Surveys and key administrative national and regional sources are also employed. Due to the several data sources, considerable variability remains across countries in the coverage, periodicity, quality and completeness of the original data. The health worker occupations are classified according to the latest version of the International Standard Classification of Occupations (ISCO - 08).