Assessment of rejection criteria based on absolute difference of χ² between EPINARBO and Lumba. In each case the colourmap is log|Δχ²|: (a) |Δχ²| in a log scale against the best fit (BF) χ². Rejection limit at 1.0 is shown as a dashed line; (b) Δ[Fe/H]_{LM − EP} against ΔT_{effLM − EP}; (c) ΔT_eff,LM−EP against T_eff,LM; (d) Δ[Fe/H]_{LM − EP} against [Fe/H]_LM. The data points with a white centre are those rejected when |Δχ²| > 1.0.