FRM Part II · FRM Exam Part II · Case Study: Model Risk and Model Validation
A bank's VaR model is validated by comparing its output with a simpler benchmark model built independently on the same portfolio. The two produce 99% one-day VaR figures that diverge materially. What is the most appropriate interpretation?
A material gap between a model and an independent benchmark signals potential model risk and calls for investigation of assumptions, data and implementation. Neither model is automatically right: complexity does not prove accuracy, and simplicity does not prove error. Concluding the data is flawed is also unsupported.
- AThe divergence signals possible model risk and should be investigated, since neither model can be assumed to be correctCorrect
- BThe more complex model is proven correct because complexity captures more risk factors
- CThe benchmark must be wrong because it is simpler, so the discrepancy can be ignored
- DThe divergence proves the data is flawed and no further model analysis is needed
Explanation
Benchmarking is used to highlight model uncertainty. A material gap means assumptions, data or implementation differ, and the cause must be explored. Complexity does not guarantee accuracy, and the divergence does not by itself prove a data problem.
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