Brosius Flashcards
Describe a situation in which it would be appropriate to use the link ratio method, the budgeted loss method and the least square method
- Link ratio : Use for older accident years where loss development is stable
- Budgeted loss : Use when fluctuation in loss experience is extreme and/or when past data is not available
- Least square: Use when random year to year fluctuations in loss experience is significant.
What are the special cases of the least square development method
- Link ratio : a = 0
- Budgeted loss method when b = 0
- Bornhuetter-Fergusson method when b = 1
Why the flexibility of the least square method gives an important advantage?
Since it gives more or less weight to the observed value of x as appropriate (i.e. credibility weighting)
Name 2 issues that can lead to values of a and b that do not reflect reality
- Significant changes in the nature of the loss experience
2. Sampling error
Which method should we use when a < 0 ? b < 0%
- When a < 0, our estimate of y will be negative for small values of x –> Link ratio
- When b <0, our estimate of y will decreases as x increases –> Budgeted loss method
Name 3 possible solutions for managing the bulk reserves when the reported proportion of expected losses for the current AY period is 8% higher than it should be
- Reduce the bulk reserve by a corresponding amount (Budgeted)
- Leave the bulk reserve at the same % level of expected losses (BF)
- Increase the bulk reserve in proportion of the increase of actual reported over expected reported (link ratio)
List the formulas for Q(x) and R(x) for a simple model and Poisson-binomial model. Which method correspond the best to the model?
Simple : Least square
Poisson - Binomial : BF
Name the 4 options for link ratios when using the poisson-binomial model
- Unbiaised estimate
- Minimize MSE
- Use E[Y|X]for c
- Salxmann’s iceberg technique
Name formula for Q(X) and R(X) for negative binomial, fixed prior case and fixed reporting case
It is difficult to compute a pure bayesian estimate Q since it requires knowledge of the loss and loss reporting processes. We can then use the best linear approximation. What are the 3 advantages?
- Simpler to compute
- Easier to understand and explain
- Less dependent upon the underlying distribution
Write the development formula 1. Explain the 3 different scenarios with COV(X,Y) and VAR(X)
Write the development formula with empirical data
When the least square development is not appropriate? What can we do with systematic distortions?
- Least square fit does not make sense if year to year changes in loss experience are due largely to systematic shifts or distortions in the book of business
- May fit if year to year changes are due largely to random chances
- In the case of systematic distortions, data can be adjusted before applying the least square
1) Correct for inflation by putting the years on a constant-dollar basis before fitting a line (Incurred losses)
2) If the business expands, we can divide each year’s losses with exposure to eliminate distortions
Write development formula 2 (Credibility weighintg)
Write the 3 special cases of the development formula 2