We include new data in an updated analysis of helium in low-metallicit
y extragalactic H nr regions with the goal of deriving the primordial
abundance of He-4 (Y-P). We show that the new observations of Izotov e
t al. are consistent with previous data. However, they should not be t
aken in isolation to determine Y-P, owing to the lack of sufficiently
low-metallicity points. We use the extant data in a semiempirical appr
oach to bounding the size of possible systematic uncertainties in the
determination of Y-P. Our best estimate for the primordial abundance o
f He-4 assuming a linear relation between He-4 and O/H is Y-P= 0.230 /- 0.003(stat) based on the subset of H II regions with the lowest met
allicity; for our full data set we find Y-P= 0.234 +/- 0.002(stat). Bo
th values are entirely consistent with our previous results. We discus
s the implications of these values for standard big bang nucleosynthes
is (SBBN), particularly in the context of recent measurements of deute
rium in high-redshift, low-metallicity QSO absorption-line systems.