Is Australian data really validating EGM2008, or is EGM2008 just in/validating Australian data?

Abstract. The tide-free release of the EGM2008 combined global geopotential model and its pre-release PGM2007A are compared with Australian land and marine gravity observations, co-located GPS-levelling on the [admittedly problematic] Aus-tralian Height Datum, astrogeodetic deflections of the vertical, and the AUSGeoid98 regional gravim-etric quasigeoid model. The results show that we cannot legitimately claim to truly validate EGM2008. Instead, EGM2008 confirms already-known problems with the Australian data, as well as revealing some previously unknown problems. If one wants to claim validation, then EGM2008 is validated because it can confirm the errors in our regional data. Simply, EGM2008 is a good model over Australia