Difference (ΔZ_O/H) between observed metallicity and metallicity determined through the MZR (Eqs. (7)–(9), as well as Table 2) as a function of host galaxy stellar mass. In other words, if ΔZ_O/H > 0, the observed metallicity exceeds the value predicted by the MZR, and vice versa. The figure contains metallicity estimates from Graham et al. (2023), who use the Curti et al. (2017, 2020, “C17”) method, which are compared to the Sanders et al. (2021) MZR (squares), and the Kobulnicky & Kewley (2004, “KK04”) method, which are compared to the Kobulnicky & Kewley (2004) MZR as listed in Table 2 (triangles) as well as a version of this MZR with adjusted low-mass slope (inverted triangles), as defined by Chruślińska et al. (2021). The different estimates are connected by dotted lines for the same LGRBs. For some LGRBs there is no KK04 estimate. The stellar masses were taken from Svensson et al. (2010) and Perley et al. (2016c) and corrected to a Kroupa (2001) IMF. These LGRBs have redshifts z ≤ 2.5 (see colour bar at top). Moreover, the shaded region shows σ_MZR (Eq. (10)).