In Litovsky et al. 2009 paper they stated that by using the same data,

evaluation of localization accuracy across all locations was also

conducted, yielding average RMS errors of 28° in the bilateral

condition, which is consistent with findings from other studies

(van Hoesel & Tyler 2003; Nopp et al. 2004; Schoen et al.

2005; Verschuur et al. 2005; Neuman et al. 2007).