Empirical correlation between the LIS and H I covering fractions. Red, yellow, black, and dark blue lines correspond to the 1:1, Reddy et al. (2016b), and Gazagnes et al. (2018) relations and our Bayesian linear fit (LINMIX), respectively. The points are color-coded according to the gas-phase metallicity of each source, 12 + log(O/H), and typical error bars are shown in the bottom-right corner. The blue shaded area represents the 2σ confidence interval including the intrinsic scatter of the fit. The linear correlation coefficient (r²) and intrinsic scatter over the fit (σ_y) are given. The Izotov et al. (2016a,b, 2018a,b, 2021) and Wang et al. (2019) sources are displayed in diamonds, and also included in the fit.