FRM Part II · FRM Exam Part II · Beyond Exceedance-Based Backtesting of Value-at-Risk Models
An analyst transforms PIT values u_t into z_t = Φ^-1(u_t) to test a VaR model's full distribution. Which statement best describes the advantage of this step and the expected outcome under a correct model?
Under a correct model, the transformed values z_t should be i.i.d. standard normal. This lets the analyst apply powerful parametric tests, such as the Berkowitz likelihood ratio test of zero mean, unit variance and no autocorrelation, using the full distribution rather than only exceedances.
- Az_t should be i.i.d. standard normal, allowing standard normality and independence tests such as the Berkowitz likelihood ratio testCorrect
- Bz_t should be uniform on [-1, 1], allowing a Kupiec proportion-of-failures test
- Cz_t should equal the VaR exceedance indicator, allowing a binomial test
- Dz_t should be chi-square distributed, allowing a test of tail loss magnitude only
Explanation
Applying the inverse normal CDF to i.i.d. uniform PITs gives i.i.d. standard normal variates under a correct model. This enables a likelihood-ratio test of mean zero, variance one and zero autocorrelation (Berkowitz). Exceedance-only tests like Kupiec use just the binary hit indicator.
Did you get it right without looking?
One question tells you little. A timed set on Beyond Exceedance-Based Backtesting of Value-at-Risk Models shows your real accuracy, how long you take and where you lose marks.
More Beyond Exceedance-Based Backtesting of Value-at-Risk Models questions
- A risk manager wants to backtest a bank's full predictive VaR distribution rather than only counting exceedances. She converts each day's re…
- A bank's 250 daily PIT values are transformed to z_t = Φ^-1(u_t). The sample mean of z_t is 0, the sample standard deviation is 1.40, and th…
- A risk analyst notes that Value-at-Risk (VaR) can be backtested directly by counting exceedances, but Expected Shortfall (ES) cannot be back…
- Why is backtesting ES generally considered more demanding in data terms than backtesting VaR at the same confidence level?
- Two models A and B are compared over 250 days using average quantile scores at 99%. Model A averages 0.052 and Model B averages 0.047. The d…
- A risk analyst backtests a bank's daily VaR model using the probability integral transform (PIT). For each day, she evaluates the model's fo…