Fixing soft margins
Non-parametric tolerance limits are employed to calculate soft margins such as advocated in Williamson's target zone proposal. In particular, the tradeoff between softness and zone width is quantified. This may be helpful in choosing appropriate margins. Furthermore, it offers policymakers a framework for reference in the case of changing exchange rate policy. The empirical applications include an evaluation of the EMS zone width. We also show that the procedures for calculating the soft margins are robust against alternative data-generating mechanisms.