Large population-based studies can inform us on the prevalence, incidence, natural history, treatment, correlates, and associations of disease, as well as the pattern of health care utilization. A special type of large population study encompasses the population of an entire nation. Advantages include enormous sample size and lack of selection and participation bias. These advantages are enhanced further when the databases are rich in clinical, personal, and risk factor information and when different pieces of information are linked to permit joint analysis. Once the process for data accessing is established, vast amounts of information can be obtained at minimal cost, especially when additional collection and update of information is carried out routinely for purposes inherent in medical care and/or insurance coverage and reimbursement.
Hsing AW, Ioannidis JPA. Nationwide Population ScienceLessons From the Taiwan National Health Insurance Research Database. JAMA Intern Med. 2015;175(9):1527–1529. doi:10.1001/jamainternmed.2015.3540