  The accuracy of the procedure that converts the experimentally determined
electron spectrum associated with fission of the nuclear fuels ^{235}U,
^{239}Pu, ^{241}Pu, and ^{238}U into the $\bar{\nu}_e$ spectrum is examined. By
using calculated sets of mutually consistent spectra it is shown that the
conversion procedure can result in a small $\sim$1% error provided several
conditions are met. Chief among them are the requirements that the average
nuclear charge <Z> as a function of the $\beta$ decay endpoint energy is
independently known and that the $\bar{\nu}_e$ spectrum is binned into bins
that are several times larger than the width of the slices used to fit the
electron spectrum.
