Public health approaches seek to prevent impairments to health and development by changing the behavior or exposure to risks of a specified population. Examples include immunization programs which, if accepted by a sufficient proportion of the population, will provide protection against exposure to disease. In social contexts, the effectiveness of public health approaches often depends on people wanting to behave like other people. For example, a public health approach might seek to reduce the amount of alcohol consumed by the average drinker, on the assumption that consumption among heavier drinkers will follow suit.