Herd Immunity and Positive Externalities by

Slide 3: Herd Immunity Threshold (HIT) Table SOURCE: http://en.Wikipedia.org/wiki/Herd_immunity<br>

Slide 4: Negative Externality Examples Cigarette smoking creates passive smoking for non-smokers.
A loud concert at a park creates noise at a nearby quiet neighborhood.<br>

Slide 5: Positive Externality Examples Property values for other houses in the neighborhood rise when a homeowner improves his or her house and sells it for more than it was previously worth.

Recreation space is created when a state builds a reservoir for flood control.

An industrial company provides first aid classes for employees to increase job safety. An employee is also equipped to save lives outside the factory.<br>

Slide 6: Vocabulary
Externality: A cost and/or benefit that spills over to a third party not directly involved in the production or consumption of a good or service.

Herd immunity: The resistance to the spread of a contagious disease within a population that results if a sufficient high proportion of individuals are immune to the disease, especially through vaccination.

Negative externality: A cost that spills over to a third party not directly involved in the production or consumption of a good or service.

Positive externality: A benefit that spills over to a third party not directly involved in the production or consumption of a good or service.<br>