  In most star formation history (SFH) measurements, the reported uncertainties
are those due to effects whose sizes can be readily measured: Poisson noise,
adopted distance and extinction, and binning choices in the solution itself.
However, the largest source of error, systematics in the adopted isochrones, is
usually ignored and very rarely explicitly incorporated into the uncertainties.
I propose a process by which estimates of the uncertainties due to evolutionary
models can be incorporated into the SFH uncertainties. This process relies on
application of shifts in temperature and luminosity, the sizes of which must be
calibrated for the data being analyzed. While there are inherent limitations,
the ability to estimate the effect of systematic errors and include them in the
overall uncertainty is significant. Effects of this are most notable in the
case of shallow photometry, with which SFH measurements rely on evolved stars.
