  The physics program of future lepton colliders such as the ILC, will benefit
from a jet energy resolution in the range 3-4%. The International Large
Detector (ILD) reaches this goal over a large range of jet energies. In this
paper, we report on the dependence of the simulated ILD performance on various
parameters of its silicon-tungsten ECAL. We investigate the effects of dead
areas in the silicon sensors, the thickness of the PCB at the heart of the
detector, and the robustness of its performance with respect to dead channels,
noise, mis-calibration and cross-talk.
