Figure 1From: Early detection of influenza outbreak using time derivative of incidenceAn episode of care. The medical records for influenza within 10 days from the most recent medical record of the same person are bound to a single episode of care. Then, we choose the first medical record of each episode of care, which is marked by a red dot, as an incidence of influenza. Here, yellow dots mean medical records within the same episode of careBack to article page