The effective ionic charge, Z eff , is determined through the integration of soft x-ray tomography and charge exchange recombination spectroscopy impurity density measurements in the Madison Symmetric Torus. Z eff is found is be 2.3 ± 0.1 in the core of high temperature, high current, improved confinement discharges, with a slightly hollow profile peaking near mid-radius. A Bayesian probability framework, developed as part of an ongoing effort in Integrated Data Analysis, was used to incorporate these two measurements. This framework provides a method to address different systematic and statistical uncertainties associated with each diagnostic and to test hypothetical contributions to Z eff against the existing data set. The combined analysis provides much higher confidence in the result than previous single-diagnostic attempts to characterize Z eff using near-infrared bremsstrahlung or x-ray spectroscopy.