  We compare distance resolved, absolute proper motions in the Milky Way
bar/bulge region to a grid of made-to-measure dynamical models with well
defined pattern speeds. The data are obtained by combining the relative VVV
Infrared Astrometric Catalog v1 proper motions with the Gaia DR2 absolute
reference frame. We undertake a comprehensive analysis of the various errors in
our comparison, from both the data and the models, and allow for additional,
unknown, contributions by using an outlier-tolerant likelihood function to
evaluate the best fitting model. We quantify systematic effects such as the
region of data included in the comparison, the possible overlap from spiral
arms, and the choice of synthetic luminosity function and bar angle used to
predict the data from the models. Resulting variations in the best-fit
parameters are included in their final errors. We thus measure the bar pattern
speed to be ${\Omega}_b=33.29\pm1.81 \mathrm{km \, s^{-1} \, kpc^{-1}}$ and the
azimuthal solar velocity to be $V_{\phi,\,\odot} = 251.31 \pm 1.95 \mathrm{km
\, s^{-1}}$. These values, when combined with recent measurements of the
Galactic rotation curve, yield the distance of corotation, 6.5 < $R_{CR}$ [kpc]
< 7.5, the outer Lindblad resonance (OLR), 10.7 < $R_{OLR}$ [kpc] < 12.4, and
the higher order, m = 4, OLR, 8.7 < $R_{{OLR}_4}$ [kpc] < 10.0. The measured
pattern speed provides strong evidence for the "long-slow" bar scenario.
