IX. THE ROLE OF THE ACTUARY
This study note has outlined some of the fundamentals of insurance. Now the question is: what is
the role of the actuary?
At the most basic level, actuaries have the mathematical, statistical and business skills needed to
determine the expected costs and risks in any situation where there is financial uncertainty and
data for creating a model of those risks. For insurance, this includes developing net premiums
E
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(benefit premiums), gross premiums, and the amount of assets the insurer should have on hand to
assure that benefits and expenses can be paid as they arise.
The actuary would begin by trying to estimate the frequency and severity distribution for a
particular insurance pool. This process usually begins with an analysis of past experience. The
actuary will try to use data gathered from the insurance pool or from a group as similar to the
insurance pool as possible. For instance, if a group of active workers were being insured for
healthcare expenditures, the actuary would not want to use data that included disabled or retired
individuals.
In analyzing past experience, the actuary must also consider how reliable the past experience is as
a predictor of the future. Assuming that the experience collected is representative of the insurance
pool, the more data, the more assurance that it will be a good predictor of the true underlying
probability distributions. This is illustrated in the following example:
An actuary is trying to determine the underlying probability that a 70-year-old woman will die
within one year. The actuary gathers data using a large random sample of 70-year-old women
from previous years and identifies how many of them died within one year. The probability is
estimated by the ratio of the number of deaths in the sample to the total number of 70-year-old
women in the sample. The Central Limit Theorem tells us that if the underlying distribution has a
mean of p and standard deviation of σ then the mean of a large random sample of size n is
approximately normally distributed with mean p and standard deviation
σ
n
. The larger the size
of the sample, the smaller the variation between the sample mean and the underlying value of p .
When evaluating past experience the actuary must also watch for fundamental changes that will
alter the underlying probability distributions. For example, when estimating healthcare costs, if
new but expensive techniques for treatment are discovered and implemented then the distribution
of healthcare costs will shift up to reflect the use of the new techniques.
The frequency and severity distributions are developed from the analysis of the past experience
and combined to develop the loss distribution. The claim payment distribution can then be
derived by adjusting the loss distribution to reflect the provisions in the policies, such as
deductibles and benefit limits.
If the claim payments could be affected by inflation, the actuary will need to estimate future
inflation based on past experience and information about the current state of the economy. In the
case of insurance coverages where today’s premiums are invested to cover claim payments in the
years to come, the actuary will also need to estimate expected investment returns.
At this point the actuary has the tools to determine the net premium.
The actuary can use similar techniques to estimate a sufficient margin to build into the gross
premium in order to cover both the insurer’s expenses and a reasonable level of unanticipated
claim payments.
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Aside from establishing sufficient premium levels for future risks, actuaries also use their skills to
determine whether the insurer’s assets on hand are sufficient for the risks that the insurer has
already committed to cover. Typically this involves at least two steps. The first is to estimate the
current amount of assets necessary for the particular insurance pool. The second is to estimate the
flow of claim payments, premiums collected, expenses and other income to assure that at each
point in time the insurer has enough cash (as opposed to long-term investments) to make the
payments.
Actuaries will also do a variety of other projections of the insurer’s future financial situation under
given circumstances. For instance, if an insurer is considering offering a new kind of policy, the
actuary will project potential profit or loss. The actuary will also use projections to assess
potential difficulties before they become significant.
These are some of the common actuarial projects done for businesses facing risk. In addition,
actuaries are involved in the design of new financial products, company management and strategic
planning.
X. CONCLUSION
This study note is an introduction to the ideas and concepts behind actuarial work. The examples
have been restricted to insurance, though many of the concepts can be applied to any situation
where uncertain events create financial risks.
Later Casualty Actuarial Society and Society of Actuaries exams cover topics including:
adjustment for investment earnings; frequency models; severity models; aggregate loss models;
survival models; fitting models to actual data; and the credibility that can be attributed to past data.
In addition, both societies offer courses on the nature of particular perils and related business
issues that need to be considered.