  We introduce the MINERvA Analysis Toolkit (MAT), a utility for centralizing
the handling of systematic uncertainties in HEP analyses. The fundamental
utilities of the toolkit are the MnvHnD, a powerful histogram container class,
and the systematic Universe classes, which provide a modular implementation of
the many universe error analysis approach. These products can be used
stand-alone or as part of a complete error analysis prescription. They support
the propagation of systematic uncertainty through all stages of analysis, and
provide flexibility for an arbitrary level of user customization. This
extensible solution to error analysis enables the standardization of systematic
uncertainty definitions across an experiment and a transparent user interface
to lower the barrier to entry for new analyzers.
