IR spectroscopic channel extends the redshift overage of the LGRB host metallically sample out to [*z*]{} = 2.47[^1]. In combination [@xshooter_survey] and [@stats_paper] provide a sample of sufficient size and redshift range to allow division into different redshift bins as necessary to study the evolution of the LGRB metallically distribution with redshift as we will do here.

Two objects overlap between the samples (LGRBs 050824 and 051022) whose measured metallicity values differ by 0.23 and 0.31 dex between the [@stats_paper] and [@xshooter_survey] estimates respectively. In the combined sample the duplication has been removed and the flux measurements from the [@xshooter_survey] spectroscopy used. \[dupout\] We standardize on the [@xshooter_survey] spectroscopy because they publish errors on their line flux values whereas the LGRB 050824 line fluxes of [@Sollerman2007] (used in @stats_paper) and the LGRB 051022 line fluxes of [@Levesque2] do not. Furthermore the [@stats_paper] metallically for LGRB 051022 was determined from equivalent width observations [@conference_proceedings], not line flux values, which while an established technique [@KobulnickyPhillips], introduces an difference in method that we can easily avoid here. Note that the metallicity values and relative measured line fluxes for the host of LGRB 051022 have previously been noted as being significantly different between the 