Epidemiological Field Work in Population-Based Studies

Field work in epidemiological studies consists of collecting data in natural and experimental settings to answer research questions or test hypotheses about the origins, distribution, and control of disease in populations. Field data can be collected directly and indirectly. Although direct data collection traditionally includes collecting biological samples such as blood and saliva, epidemiologists also collect data about the health of populations by contacting respondents through the telephone, mail, or online. To study a community’s use of preventative health services (such as influenza vaccinations), for example, a team of epidemiologists can conduct in-person or telephone interviews or administer written, computer-assisted or online surveys. Indirect data collection includes reviewing written, oral, and visual records of respondents’ thoughts and actions and observing them in their natural or experimental environment. To study the extent to which a health care system’s medical providers adhere to recommended guidelines for preventative health care, for instance, a team of epidemiologists might review a sample of medical records to identify which preventative services were used and by whom. If the team were interested in understanding why preventative services were (or were not) used, it might review transcripts of audio or videotapes of selected physician and patient encounters.