Actuarial Assumption

An actuarial assumption is an estimate of an uncertain variable input into a financial model, normally for the purposes of calculating premiums or benefits. For example, a common actuarial assumption relates to predicting a person's lifespan, given their age, gender, health conditions and other factors. Actuaries use large tables of statistical data which correlate the uncertain variable to a variety of key predictive variables. Given the values for the predictive variables a sound actuarial assumption can be made for the uncertain variable.

Actuarial assumptions are important because they allow for the equitable transfer of risk in many situations. For instance, when underwriting life insurance policies, it is important to understand the probability that the insured might pass away during the policy period. Given an accurate actuarial assumption for this probability, it is easy to calculate a fair premium for such a policy. Without the ability to accurately figure these probabilities, very few people would be willing to provide insurance. If they were, it would have to be more expensive to allow room for unexpected losses.