  We perform an extraction of alpha_s based on sum rules involving isovector
hadronic tau decay data. The particular sum rules employed are constructed
specifically to suppress contributions associated with poorly known higher
dimension condensates, and hence reduce theoretical systematic uncertainties
associated with the treatment of such contributions which are shown to be
present in earlier related analyses. Running our results from the n_f=3 to
n_f=5 regime we find alpha_s(M_Z^2)=0.1187(16), in excellent agreement with the
recently updated global fit to electroweak data at the Z scale, 0.1191(27), and
other high-scale direct determinations.
