Before revision:  The model risk measure is defined in terms of the expected value and standard deviation of the loss given by the hedging strategy at a given time horizon . It has been assumed that the market volatility surface is driven by Heston 's dynamics calibrated to market for a given time horizon  .
After revision:  The model risk measure is defined in terms of the expected value and standard deviation of the loss given by the hedging strategy at a given time horizon for a chosen significance level. The reference model has been chosen to be Heston calibrated to market for a given time horizon .