Actuarial Science Foundations Module
Foundational actuarial reasoning
The Actuarial Science Foundations Module connects probability, finance, and business context. Understand expected value, present value, risk pooling, diversification, and the difference between risk and uncertainty. Know how cash flows, timing, and contingent events combine in actuarial problems. Identify the stakeholder, the decision, and the relevant time horizon. A calculation is only part of the answer; the actuary must explain what it means and what assumptions drove it.
Traps and judgment
Common traps include treating an expected value as a guaranteed outcome, ignoring the cost of capital, and using a single scenario as if it were certain. Distinguish frequency, severity, and aggregate loss. In pooling, more independent risks reduce relative variability but do not eliminate systemic risk. Check units, time periods, and whether a rate is annual or per period. Round only at the end, and keep enough precision for the final answer.
Worked rule
A portfolio has a 1% chance of a 1,000,000 loss and a 99% chance of no loss. The expected loss is 10,000, but the risk is not trivial because the tail loss is large. A rule of thumb is to report both expected cost and tail exposure. The trap is saying the risk is only 10,000; that is the average, not the worst case or the capital needed. Match the risk measure to the decision.