Lead time is between an easy diagnosis of a disease with improved screening and the usual point at which a medical professional can diagnose it based on the presentation of symptoms. The bias occurs when people misconstrue the lead time to mean the average patient now experiences better outcomes. For example, if a doctor can usually diagnose Huntington’s disease at 50, and the patient will die at 65, this would be 15 years between diagnosis and death. Early genetic testing as a newborn could allow for 65 years of “survival” of the disease before the person dies at the usual age of 65.