Comparison between three star formation models (top, middle, and bottom) and PHANGS measurements of the population-average ${ϵ}_{\mathrm{ff}}^{\mathrm{obs}}$ in 1.5-kpc wide hexagonal apertures (see Figure 1) plotted against the average cloud-scale velocity dispersion $⟨{\sigma }_{\mathrm{mol}}^{\mathrm{cloud}}⟩$ in each aperture (see text). In the left (right) panels, measurements are color-coded by $⟨{\mathrm{\Sigma }}_{\mathrm{mol}}^{\mathrm{cloud}}⟩$ (⟨α_vir⟩) and shown alongside lines illustrating fixed-Σ (fixed-α_vir) predictions from turbulence-regulated SF models at three representative values of Σ (α_vir) (see text). As in Figure 1, all models adopt ϵ_core = 0.5, b = 0.87; the gas sound speed, c_s = 0.3 km s⁻¹ (see the main text for definitions of these quantities); and, for comparison, the same definition for the critical density, given by Eq. (4).