  We evaluate the contribution of cosmic microwave background (CMB)
polarization spectra to cosmological parameter constraints. We produce
cosmological parameters using high-quality CMB polarization data from the
ground-based QUaD experiment and demonstrate for the majority of parameters
that there is significant improvement on the constraints obtained from
satellite CMB polarization data. We split a multi-experiment CMB dataset into
temperature and polarization subsets and show that the best-fit confidence
regions for the LCDM 6-parameter cosmological model are consistent with each
other, and that polarization data reduces the confidence regions on all
parameters. We provide the best limits on parameters from QUaD EE/BB
polarization data and we find best-fit parameters from the multi-experiment CMB
dataset using the optimal pivot scale of k_p=0.013 Mpc-1 to be {omch2, ombh2,
H_0, A_s, n_s, tau}= {0.113, 0.0224, 70.6, 2.29 times 10^-9, 0.960, 0.086}.
