2.2.1 Top-down studies

Top-down COI studies make use of data concerning the entire given population, including the entire range of diseases affecting that population on the national level, and then separate the diseases one by one to estimate their individual costs. In Korea, the most favored source of data for such studies is the billing information kept by the NHIS. Billing data provide a convenient glimpse into the total socioeconomic costs of illnesses in the given society. However, the vast scope of these data can easily lead researchers to include in their estimates expenses and costs that are not directly related to the given illness (e.g., costs of prescriptions or medical tests due to sub-diseases).
