How well do domain wall fermions realize chiral symmetry?

In the domain wall fermion formulation, chiral symmetry breaking in full QC D is expected to fall exponentially with the length of the fifth dimension. We measure the chiral symmetry breaking due to a finite fifth dimension in two ways, which can be effected differently by finite volume and explicit fermion mass. For quenched QCD the two methods generally agree, except for the largest extent of the fifth dimension, which makes the limit uncertain. We have less data for full QCD, but see exponential suppression for the me thod where we have data.