  Building high-fidelity quantum computers requires efficient methods for the
characterization of gate errors that provide actionable information that may be
fed back into engineering efforts. Extraction of realistic error models is also
critical to accurate simulation and design of quantum circuits, including those
used in quantum error correction. We provide a method for determining the
parameters corresponding to decoherence in a model gateset. We demonstrate that
this method is robust to SPAM and pulse area errors, and describe a simple and
intuitive method for interpreting the quality and precision of the resulting
error model.
