Three-particle correlations together with two-particle correlations provide experimental information on thermalization and (in)coherence of the particle-emitting source produced in high energy collisions. We present here a consistent analysis of two- and three-particle correlations measured at PHENIX in $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions. In order to extract an experimental measure of the thermalization of the source, one has to extrapolate both correlation functions to zero relative momenta, and errors in the assumed source shape can bias the results. To obtain accurate estimates and systematic errors we analyze both 2- and 3-particle correlation functions in a consistent manner using both Gaussian and Levy sources.