Vaccines as a Positive Externality

A science-based example of a positive externality is vaccinations. Vaccinations work based on the number of people in the population who are vaccinated. Once a certain threshold is reached, the disease can't spread effectively and is essentially eliminated. As long as enough people are vaccinated, others who choose not to be still get to enjoy that positive externality at no cost. These are what economists call freeloaders. Economists like the golden rule: Do unto others as you would have the...

 Externalities

In every economic transaction there is a willing buyer and a willing seller. and they agree on a price that benefits both. But there are spillover effects in many economic transactions—costs and/or benefits that are transferred to third parties. Friedman called these spillovers "neighborhood effects." Today, most economists call them "externalities. At their most basic, externalities don't have to involve buying and selling. If you smoke in a restaurant instead of stepping outside it's easi...