What is the cause of uninsured patients?

Not everyone has insurance through their work. Many people are uninsured or underinsured by choice or because they really just don't have enough money.

Economic analysis would also suggest that insured people overuse the system, driving up prices for everyone else, causing health care to become more expensive for everyone else. Also, the moral hazard exists where doctors have an incentive to overmedicate/overtreat patients because they get paid to do so. This drives up the cost of insurance, making it even more expensive.