Residuals in the H-band dereddened magnitude PL relation as a function of iron abundance. Panel a: original Romaniello et al. (2008) sample of 22 LMC Cepheids, with photometry from Persson et al. (2004). Panel b: same sample, but with the iron abundances as revised here. Panel c: SH0ES sample of 68 LMC Cepheids, with iron abundances as measured here and photometry from Riess et al. (2019). To guide the eye, in all panels, the red line indicates a metallicity dependence of the Cepheid PL of γ = −0.2 mag dex⁻¹, which is often quoted in the recent literature (e.g., Riess et al. 2019; Breuval et al. 2021; Ripepi et al. 2021).