Siewart Flashcards
loss ratio approach: advantages
- Can be used when no data available or when data is immature
- LR estimates can be consistently tied to pricing programs
- Relies on more credible pool of company and industry experience
loss ratio approach: disadvantages
- Ignores actual emerging experience (not as useful for mature years)
- Industry data may not be applicable to the company’s book of BoB
per occurrence excess loss
P*E*x
Premium*ELR*per occurrence charge/excess ratio
per aggregate excess loss
P*E*(1-x)*phi
phi is per aggregate charge/aggregate ratio
ultimate excess loss formula
P*E*x+P*E*(1-x)*phi
implied development approach process
- Develop full coverage losses to ultimate
- Determine ultimate excess losses = ult full coverage – ult limited
implied development approach: advantages
- Provides estimate of excess loss at early maturities even when excess loss have not emerged
- estimates the ultimate excess losses using more stable development patterns from the limited loss triangle
- Estimating deductible loss help determine asset value represented by service revenue
*limited losses develop faster and is more stable than excess
implied development approach: disadvantage
-Does not explicitly recognize excess loss development
why is it appropriate to index deductible for inflation
because it keeps the proportion of deductible/excess losses constant about the limit from year to year
direct development approach
Focus on excess development directly
direct development approach: advantage
-Explicitly recognizes excess loss development
direct development approach: disadvantages
- Excess factors tend to be overly leveraged and extremely volatile
- If excess losses have not yet emerged, cannot estimate IBNR
formulas for development factors for LDFL and XSLDFL
LDFL = LDF*RL/RtL
XSLDFL=LDF*(1-RL)/(1-RtL)
R: severity relativity (limited severity/unlimited severity), ratio of reported losses
R should decrease with time
these formulas can be used for CDFs and LDFs, the formula above is for CDF but can adjust to make LDF by adjusting RL
unlimited LDF formula aka credibility formula
LDF=RtL*LDFL+(1-RtL)*XSLDFL
weighted average of excess and limited LDFs
Credibility weighting/BF
-Relies on weighting indications based upon actual experience (direct development) with expected values (loss ratio approach)
U=Z*O*LDF + (1-Z)*E
O: observed loss at time t, LDF: age to ultimate, E: expected ult loss
*If set Z=1/LDF, end up with BF estimate for ultimate loss
U=O + E*(LDF-1)/LDF
*E is expected excess loss and LDF is XSLDF