Previous research has shown that opinions about a treatment can differ depending on how its outcome is described. Describing the effect of a treatment to prevent a disease is tricky. Many people would never get the disease even without taking the medicine. In a person who would become ill without the medicine, the treatment may either totally prevent the disease or postpone it to a later stage in the person's life. Other people will get the disease at the same time as they would without treatment. A common way to describe the effect of a treatment is to define the number of people who must be treated to prevent 1 person from getting the disease. However, this method does not take into account that treatment delays—as opposed to prevents—disease in some people.