  We present a new determination of $\hat{q}$, the jet transport coefficient of
the quark-gluon plasma. Using the JETSCAPE framework, we use Bayesian parameter
estimation to constrain the dependence of $\hat{q}$ on the jet energy,
virtuality, and medium temperature from experimental measurements of inclusive
hadron suppression in Au-Au collisions at RHIC and Pb-Pb collisions at the LHC.
These results are based on a multi-stage theoretical approach to in-medium jet
evolution with the MATTER and LBT jet quenching models. The functional
dependence of $\hat{q}$ on jet energy, virtuality, and medium temperature is
based on a perturbative picture of in-medium scattering, with components
reflecting the different regimes of applicability of MATTER and LBT. The
correlation of experimental systematic uncertainties is accounted for in the
parameter extraction. These results provide state-of-the-art constraints on
$\hat{q}$ and lay the groundwork to extract additional properties of the
quark-gluon plasma from jet measurements in heavy-ion collisions.
