Ch 21: Assumptions 1 Flashcards
Background on assumptions
What is the key reason assumptions are used for? (1)
What key risk does setting assumptions introduce? (1)
What kind of risks can be somewhat mitigated by appropriate matching of assets? (3)
- Assumptions used by insurers for variety of reasons, mostly assessng eventual cost of liabilities (pricing, reserving and ongoing profitability measurement)
- Setting assumptions may => parameter risk: want to reduce this
- Not easy finding matched assets protecting from actual experience different to expected, can sometimes reduce following risks from investment matching:
- Investment risk: relates return required meet current liabilities for future payouts
- Inflation risk: relates increase in inflation-linked liabilities + liabilities behaving approximately in line with inflation (eg expenses)
- Marketing risk: ability to satisfy policyholders in relation to any investment-linked/discretionary benefits.
Best estimate mortality:
List 2 seperate parts of moratlity to be considered when setting best estimate mortality assumptions (2)
- Base mortality: initial rate of mortality, the main demographic assumption for pricing/evaluating life insurance contracts
- Mortality trend: how mortality rate changes over time
Outline a general process for setting assumptions (5)
- Investigate past experience; make past best estimate parameters; appropriate in context of historical conditions/then-circumstances
- Consider future conditions (including commercial and economic environment ) during period for which assumptions will be used
- Determine future best estimates assumptions, given expected future conditions
- Extent of (a) relying past data vs (b) allowing for other factors, depends on data credibility/relevance + parameter’s predictability
- Adjust best estimates with margin. Size of margin depends on:
- purpose for which model is required
- degree of risk associated with parameter
- sensitivity of results for a given parameter
Best estimate mortality: base mortality derivation
Describe how to derive best estimate base mortality rates, in terms of
rates reflecting future experience (3)
- Rates should reflect expected future experience of lives to be insured by contract being priced, in terms of
- target market: affected by distribution channel
- underwriting controls:
- expected experience change: since last historical investigation, to point assumptions will apply on average (usually 10 - 15 yrs)
- The company will usually use standard mortality tables and adjust them for expected future experience
Best estimate mortality: base mortality derivation
Describe how to derive best estimate base mortality rates, in terms of
what rates are actually based on + adjustments (7)
- Base rates usually uses adjusted rates from standard table
- saves resources
- protects against errors eg inappropriate graduation
- sufficient data: analysis own experience=> derive adjustments
- data must be over _enough years (_adequate volume), but also few enough years (prevent excessive heterogeneity from trends over time)
- analysis divide data into relevant homogenous groups
- further adjustments if different experience expected from that which analysed data relate (target market, underwriting , distribution method)
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Best estimate mortality: base mortality derivation
Describe how to derive best estimate base mortality rates, in terms of
data sources (6)
- Data sources which can be used for adjustments
- own past experience with that product,
- own past experience with similar product(s),
- reinsurance data
- industry data i.e. standard tables
- international data
- national statistics
Best estimate mortality: base mortality derivation data sources
In using data for adjustments when deriving best estimate base mortality rates, list some pros/cons related to the following data sources which may be used:
Industry wide investigations (3)
Population mortality statistics (2)
Reinsurer data (5)
- Industry wide investigations
- useful for contracts where no standard table exists
- good for showing trends, since trends in own data might be due to statistical variation
- not 100% suitable since not based on insurer’s particular PHs
- Population mortality statistics
- useful for showing trends if re-examined at regular intervals in past
- not 100% suitable since not based on insurer’s particular PHs
- Reinsurer data
- Ads
- access to mortality experience of many direct writers
- may be most relevant data available
- Disads
- relates to large number of different companies
- may have little/no suitable data
- comes with a cost: cost of reinsurance
- Ads
Best estimate mortality: mortality trends
What do we meant by ‘mortality trend’? (1)
State 2 circumstances where the estimation of future mortality improvements is particularly important (2)
- The mortality trend relates to how the rate of mortality changes over time.
- Estimating future mortality improvements is particular important:
- for policies with longevity risk e.g. annuities
- when rates are guaranteed rather than reviewable
Describe how we might consider expected changes in mortality over time
Different approaches used to project mortality trends (3)
Considerations to the product (2)
- Different approaches to project mortality trends over time:
-
expectations: uses expert opinion + subjective judgement to specify range of future scenarios
- can implicity include all relevant knowledge, incuding quantitative factors
- subjective and subject to bias
-
extrapolation of historical trends
- project historical mortality trends into the future
- some subjectvity: choice of period to determine trends
-
explanatory projection techniques,
- modelling bio-medical processes that cause death
- only effective to extent process understood and mathematically model-able
-
expectations: uses expert opinion + subjective judgement to specify range of future scenarios
- Considerations should also be given to the product e.g.
- important for contracts paying significant death benefit
- important for annuities where increased longevity is a risk
- not important for single premium savings contracts
Best estimate mortality: mortality trends
State how each of the following might be taken into account when making projections of future mortality:
- cohort effect
- the combined effects of multiple factors
- random effects
- Cohort effect
- each year of birth cohort is modelled seperately, allowing for specific mortality improvemebt rates by cohort (as well as by age and sex)
- Multi-factor effects
- Use multi-factor predictive modelling techniques (eg. generalised linear models), accounting for personal attributes along with external factors affecting mortality, allowing for any correlations and interactions between them.
- Random effects
- Use stochastic modelling (e.g. Lee-Carter or P-spline method)
Morbidity assumptions
What factors/kind of rates should we consider when setting morbidity assumptions (4)
- Key factors/assumptions
- Disability incidence rate and duration for IP
- Incidence rate for CI
- Incidence and amount for LTCI
- Impact of benefit size on assumptions
Morbidity assumptions
Expand briefly on how size of benefit may impact morbidity assumptions (4)
- Impact of benefit size on assumptions
- For IP, CI, and most LTCI, benefit amount fixed, so no assumption needed for this
- But may be correlation between incidence rates and benefit size
- Only for very large policies, may insurer want to alter assumptions, to relfect better claims experience from
- PH belonging to higher socio-economic class
- stricter level of underwriting
Morbidity rates: Disability incidence and duration for IP
Describe how these rates may be determined (4)
What factors might affect the transition intensities (5)
Describe how rates are used (2)
Describe issues surrounding estimating these rates (3)
How might we control parameter uncertainty for these rates? (3)
- Benefits for IP can be modelled using a multi-state approach
- needs transition intensities (claim inception, recoveries, death)
- calculated for homogenous groups
- duration: revovery may differ vastly by duration in force
- disability type: recovery may dif vastly by disability type
- may seperate second/subsequent incidences: as more likely to claim in future
- Intensities influenced by
- PH characteristics: identified at underwriting
- prod design features: replace ratio/rehab benefits
- economic morale: low => more likely claim
- government welfare provision
- tax: on premiums (discourage sales), relief on prems (enoucourage sales), way insurer is taxed, tax rates involved changing over time
- Intensities used to calc transitions probabilities
- then construct projected numbers/proportions in each state at future ages.
- can be used to calc claim inception rates/disability annuity values
- Issues surrounding estimating rates
- Data limitations is the main issue
- Published insurance incidence data has limited credibility
- Worldwide stats may not be relevant
- Controlling parameter uncertainty
- Assuming larger risk margins
- Issuing products with reviewable premiums/charges
- Reinsurance
Morbidity rates: Incidence rate for CI
What factors influence claim distribution rates for CI (4)
What kind of factors complicate modelling/setting of assumptions (2)
- May be necessary to estimate significant number of distributions (40+) if each condition modelled seperately, plus allowance for future trends
- Other influences claim distribution (other than trends), include
- advancement in medical science (cures=> more windfalls)
- diagnosing conditions earlier (more claims)
- simple/more readily available operations (more claims)
- influence new and existing business seperately
- new business, can adjust premiums accordingly
- existing business, can only adjust in force prems if revieawable
- Factors which complicate modelling/setting assumptions
- may need to model seperately model claims defitions which are disease-based and/or treatment-based (eg coronary artery bypass, major organ transplant, heart valve replace)
- guaranteed and reviewable alternatives
- lack of data, only cancers/heart attacks will provide enough data…otherwise hasn’t really been around long enough
Morbidity rates: Incidence and amount for LTCI
What key assumptions do we need to estimate for LTCI? (2)
What are important factors for LTCI contract assumptions? (5)
What issues arise when estimating necessary assumptions? (3)
- Estimate distribution of
- claim frequency
- claim amount (if funding for care)
- Important influences for LTCI assumptions
- Medical advancements
- Transition rates: improved health may reduce inception rates and rates for people moving to higher ben-levels
- Mortality rate: improved health=> people needing benefits for longer
- Costs: changing med care may => higher costs e.g. more expensive procedeurs
- Economic factors
- inflation: big problem if benefits are indemnity based
- demand (for LTC) vs supply, usually demand is greater, leading to inflation heaveir than economic inflation
- Medical advancements
- Issues arising when estimating necssary assumptions
- Data limitations
- Little data on claim frequency to base estimates of future transition rates
- Absence of insurance statististics (industry data)