How well do domain wall fermions realize chiral symmetry?

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