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CIA General Meeting. October 19-20, 2006 Chicago, Illinois. Session IP-31. Stochastic Models: Application to LTD. When is a stochastic model appropriate? Why stochastic LTD? How?. Stochastic LTD Models. Ideas presented are very Blue Sky My goal to provoke thought Not that hard to do
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CIA General Meeting October 19-20, 2006 Chicago, Illinois Session IP-31
Stochastic Models: Application to LTD • When is a stochastic model appropriate? • Why stochastic LTD? • How?
Stochastic LTD Models • Ideas presented are very Blue Sky • My goal to provoke thought • Not that hard to do • Excel model
When Are Stochastic Models Appropriate? • When the loss model has • a long or heavy right tail • A “cliff” or trigger point • Dependencies of Risk
Looking At LTD Models • Traditionally viewed as a life annuity • We can also view these as a random variable with probability distribution
Why Not Look at LTD This Way? Heavy tail Trigger Point
Dependencies of Risks Between Claims • LTD Experience is influenced by • Economic conditions • Geographic location • CPP policy • Court decisions • Legislation • All of these lead to a dependency between claims
Dependencies of Risks Between Years • Relationship between incidence and termination rates • High incidence rates may mean more softer claims • Higher termination rates in subsequent years • Low incidence rate may mean “harder” claims • Cyclical termination rates • Claims clean up focuses on soft claims • Followed by period of low termination rates • High turnover in adjudicators leads to low terminations • Followed by period of high termination rates • This year’s experience influences next year’s experience
Simple Stochastic Model • 1000 Trials • Each trial represents one possible outcome for the portfolio • For each trial • Simulate the time on claim for each life • Use CIA LTD table to determine distribution of time on claim • Sum the PVs for all lives
Test Case 1 • 500 lives from a real LTD block • Mature block of claims • High female content
Test Case 1 Results • Mature block of 500 claims • Results fairly stable • Limited up side risk
Test Case 2 • Subset of Test Case 1 • 100 lives within 2 years of disability • Representative of new LTD group
Test Case 2 Results • Note a 5% Pad indicates 95% of monthly termination rates • Results less stable (Smaller group, within Own Occ period, younger lives)
Does the law of large numbers apply? • Test Case 1 indicates that risk is greatly reduced in a large, mature block • Good experience offsets bad • But … • Cyclical nature of LTD means that all groups have bad years together • If we write refund LTD, we give the good experience back and keep the bad
Uses For Stochastic LTD Models • Supplement not replace deterministic models • Better understanding of risks • Stop loss and Durational Pooling charges • Refund LTD reserves
Accounting for Dependencies of Risks • Add a random variable • allow for good or poor years • affects all lives equally • key impact in early years • Modification to termination probability for each year • Autoregressive component for cycles?