Health care common sense

A good post here:  Unique economics of healthcare

"Health care is obviously not like most other parts of the economy. As I said last week medical services are credence goods - goods which we don’t know whether we need, and even once we’ve consumed them, still don’t know if they were good value. In economic terms, these goods suffer from the worse of possible information failures, particularly with respect to the asymmetry of information between the seller (in this case the doctor) and the consumer. 

For these goods the demand curve may slope any which way, and people are often left to use price as the only signal of quality (or quantity for that matter). This means that a socially optimal level of medical service provision cannot be determined using basic marginal economic analysis. 

Not only that, but there are substantial positive externalities to most health care services. Vaccinations are the obvious example, but the same principle applies more broadly."