In the fields of<unk> s and public health, a<unk>  <unk> , also called a health and<unk>  (HDSS), gathers longitudinal health and<unk>  data for a dynamic cohort of the total population in a specified geographic area. An HDSS is created by first executing a census of households in the area as a baseline, followed by regular visits to each household to gather health and<unk>  data. The cohort is dynamic in that members are added through birth or immigration and members are subtracted through death or emigration. Tracking population migration is particularly important for understanding of HDSS data. In developing countries, there is commonly a lack of health and<unk>  information at the community or population level. For instance, cause of death may be unknown for deaths occurring outside of health facilities. One approach to collecting such data is the cross-sectional<unk>  and Health Surveys (DHS). HDSS provide a complement to episodic DHS by collecting longitudinally data over time, often with multiple household surveys. HDSS sites originated in the 1960s. Since then, many HDSS in developing countries have organized together in the INDEPTH network. As of 2017, INDEPTH has 47 HDSS sites following roughly 3 million people. One function of INDEPTH is to gather data across HDSS and to establish standards for data acquisition. There are other<unk>  and health data gathering programs similar to<unk>  that are not part of INDEPTH, such as the Sample Registration system in India and the Disease<unk>  Points system in China.
Demographic surveillance system
Prescription monitoring program
Clinical trial management system
Disease registry
Clinical decision support system
Phenotypic disease network 
Electronic patient-reported outcome
Public health surveillance