An important condition of health insurance is that of renewability. Some contracts are cancelable at any time upon short notice. Others are not cancelable during the year’s term of coverage, but the insurer may refuse to renew coverage for a subsequent year or may renew only at higher rates or under restrictive conditions. Thus the insured may become ill with a chronic disease and discover that upon renewal the policy excludes all future coverage for this disease. Only policies that are both noncancelable and guaranteed renewable assure continuous coverage, but these are much more expensive.

Private health insurance contracts are in general quite restricted in coverage, to the point that many consider them to be inadequate for modern conditions. They also lend themselves to abuses such as overutilization of coverage, multiple policies, and insuring for more than 100 percent of the expected loss. Health insurance, by its very existence, helps to escalate rising medical care costs; for example, insured medical losses tend to run higher than noninsured losses because physicians often charge according to “ability to pay,” and insurance increases this ability. Through insurance it is also easier to pass on rising hospital costs to the patient. Finally, since there is a tendency for those most likely to have losses to take out health insurance, an element of adverse selection exists. Careful underwriting to screen out those who are trying to take advantage of the insurance mechanism to pay for known bills is considered essential, but this undoubtedly denies coverage to many who need protection.

Groups have always been important in the insurance field, from the burial societies of the Romans and the insurance funds of the medieval guilds to the fraternal and religious insurance plans of modern times. In the 20th century private insurance companies wrote increasingly large amounts of group insurance, particularly in life insurance, health insurance, and annuities. In 1990 more than 95 percent of the industrial labour force in the United States was covered by group life and health insurance plans established by employers. Much of the impetus for these employee benefit plans came from the labour unions, which pressed for such “fringe benefits” in bargaining with employers.

Group insurance is widely used throughout the world, both in the form of private plans and as social insurance plans. Social security plans with group coverage exist in more than 140 nations. Private group plans are generally offered wherever private life and health insurance companies operate. Group life insurance is the most commonly offered plan; group health plans are government-operated in many nations. In many countries, group pension plans are common as a supplement to social insurance pension schemes.

Group insurance has been especially popular in Japan, where many employees serve a company for life. All Japanese life insurance companies offer group life insurance. Health insurance is provided by the government. Funded group pensions became popular after a 1962 tax law made contributions tax-deductible for Japanese employers. In addition, virtually all Japanese employers provide lump-sum retirement allowances to their workers.

Under group life insurance an employer signs a master contract with the insurance company outlining the provisions of the plan. Each employee receives a certificate that gives evidence of participation in the plan. The amount of insurance depends on the employee’s salary or job classification; usually the employer pays a portion of the premium and the employee pays the rest, but sometimes the employer pays the entire cost of the plan.

A major advantage of group life insurance to an employee is that usually coverage may be obtained regardless of health. An employee who leaves the group may, without a medical examination, convert the group coverage to an individual policy. The premiums on group life insurance are considerably less than on comparable individual policies, mainly because the selling and administrative costs are minimal.

Major types of health insurance written on a group basis include insurance against the losses occasioned by hospitalization, surgical expense, and disability. Hospitalization insurance is designed to cover daily room and board and other expenses. Surgical expense insurance usually provides specified allowances for physicians’ charges for various operations. Regular medical expense coverage is generally aimed at covering part of the costs of medicines and doctor calls. Major medical insurance offers the insured a large monetary coverage, designed to meet catastrophic costs of illness or accident with few restrictions as to the type of medical expense for which reimbursement is allowed. The insured must bear a percentage of any loss, usually 20 percent. Temporary disability income offers the insured a weekly indemnity for a period of up to six months if the insured is temporarily disabled and unable to work. Long-term disability extends the income for periods longer than six months. Accidental death and dismemberment insurance offers an insured or a beneficiary a lump sum; it is used widely as a form of travel accident insurance.

Under the typical group health insurance contract, the insured person enjoys several elements of protection not obtainable in individual contracts. Cancellation of coverage is not permitted unless coverage for the entire group is canceled. The insured enjoys protection against rate increases unless the rate for all members of the class is increased. Typically the group protection may be converted to some kind of individual policy, or the insured may transfer to another group plan. The insurer tends to be liberal on claims settlement because the typical premium under a group plan is large enough for the insurer to be unwilling to jeopardize the good will of the clientele through miserly claims treatment.

Most group insurance plans require that certain conditions be met. Sometimes there must be a minimum number of persons covered, such as 10 or 25. The group must also have some reason for existence other than to obtain insurance. The most usual types of groups are employees of a common employer, members of a labour organization, debtors of a common creditor, or members of a professional or trade association.

Mention must also be made of nonprofit prepayment plans (e.g., the Blue Cross–Blue Shield plans and health maintenance organizations [HMOs] in the United States), which resemble the above plans in most respects but are not operated by insurance companies. These plans often indemnify the hospital or the physician, on the basis of services performed, rather than the patient. Health insurance plans may also be established independently by large employers, labour unions, communities, or cooperatives. Outside the United States this kind of health insurance has been taken over by government programs. In Sweden, before the enactment of the compulsory insurance program in 1955, 70 percent of the population was covered by private plans. In Great Britain, before the National Health Service was instituted in 1948, about half the population was privately covered. In the Netherlands about half the population was so covered before the government program began, and there were still many private funds run by various groups.

In spite of the success of private group health insurance in the United States, it is estimated that in 1992 approximately 37 million people were without health insurance coverage. Many attempts over the years to establish universal national health insurance in the United States have failed.