Insurance, a system under which the insurer, for a consideration usually agreed upon in advance, promises to reimburse the insured or to render services to the insured in the event that certain accidental occurrences result in losses during a given period. It thus is a method of coping with risk. Its primary function is to substitute certainty for uncertainty as regards the economic cost of loss-producing events.
Insurance relies heavily on the “law of large numbers.” In large homogeneous populations it is possible to estimate the normal frequency of common events such as deaths and accidents. Losses can be predicted with reasonable accuracy, and this accuracy increases as the size of the group expands. From a theoretical standpoint, it is possible to eliminate all pure risk if an infinitely large group is selected.
From the standpoint of the insurer, an insurable risk must meet the following requirements:
1. The objects to be insured must be numerous enough and homogeneous enough to allow a reasonably close calculation of the probable frequency and severity of losses.
2. The insured objects must not be subject to simultaneous destruction. For example, if all the buildings insured by one insurer are in an area subject to flood, and a flood occurs, the loss to the insurance underwriter may be catastrophic.
3. The possible loss must be accidental in nature, and beyond the control of the insured. If the insured could cause the loss, the element of randomness and predictability would be destroyed.
4. There must be some way to determine whether a loss has occurred and how great that loss is. This is why insurance contracts specify very definitely what events must take place, what constitutes loss, and how it is to be measured.
From the viewpoint of the insured person, an insurable risk is one for which the probability of loss is not so high as to require excessive premiums. What is “excessive” depends on individual circumstances, including the insured’s attitude toward risk. At the same time, the potential loss must be severe enough to cause financial hardship if it is not insured against. Insurable risks include losses to property resulting from fire, explosion, windstorm, etc.; losses of life or health; and the legal liability arising out of use of automobiles, occupancy of buildings, employment, or manufacture. Uninsurable risks include losses resulting from price changes and competitive conditions in the market. Political risks such as war or currency debasement are usually not insurable by private parties but may be insurable by governmental institutions. Very often contracts can be drawn in such a way that an “uninsurable risk” can be turned into an “insurable” one through restrictions on losses, redefinitions of perils, or other methods.