The local heat diffusivity in H-phase discharges ranges from a factor of 1.1 to 3 lower across the plasma cross-section when compared with L-mode discharges. The corresponding measured factor of two improvement in energy confinement in the H-mode is thus a global effect and not only a consequence of improved edge confinement. These results are obtained by performing transport analysis on profile data from H- and L-phase discharges that were carefully prepared to have very similar global plasma parameters.