treatment is actually necessary; "phantom billing", billing for services not rendered; and "ganging", billing for services to family members or other individuals who are accompanying the patient but who did not personally receive any services. Perhaps the greatest total dollar amount of fraud is committed by the health insurance companies themselves. There are numerous studies and articles detailing examples of insurance companies intentionally not paying claims and deleting them from their systems, denying and cancelling coverage, and the blatant underpayment to hospitals and physicians beneath what are normal fees for care they provide. Although difficult to obtain the information, this fraud by insurance companies can be estimated by comparing revenues from premium payments and expenditures on health claims. In response to the increased amount of health care fraud in the United States, Congress, through the Health Insurance Portability and Accountability Act of 1996 (HIPAA), has specifically established health care fraud as a federal criminal offense with punishment of up to ten years of prison in addition to significant financial penalties. Automobile insurance Fraud rings or groups may fake traffic deaths or stage collisions to make false insurance or exaggerated claims and collect insurance money. The ring may involve insurance claims adjusters and other people who create phony police reports to process claims. The Insurance Fraud Bureau in the UK estimated there were more than 20,000 staged collisions and false insurance claims across the UK from 1999 to 2006. One tactic fraudsters use is to drive to a busy junction or roundabout and brake sharply causing a motorist to drive into the back of them. They claim the other motorist was at fault because they were driving too fast or too close behind them, and make a false and inflated claim to the motorist's insurer for whiplash and damage, which can pay the fraudsters up to £30,000. In the Insurance Fraud Bureau's first year or operation, the usage of data mining initiatives exposed insurance fraud networks and led to 74 arrests and a five-to-one return on investment. The Insurance Research Council estimated that in 1996, 21 to 36 percent of auto-insurance claims contained elements of suspected fraud. There is a wide variety of schemes used to defraud automobile insurance providers. These ploys can differ greatly in complexity and severity. Richard A. Derrig, vice president of research for the Insurance Fraud Bureau of Massachusetts, lists several ways that auto-insurance fraud can occur,