The SFR surface density as a function of the molecular gas surface density per freefall time for our star-forming regions (black circles with 1σ uncertainties) is compared with additional models from the literature. By construction, the models shown in both panels have slope = 1. (Left) The “local” model of B. G. Elmegreen (2018) (dark-red solid lines), which leaves the efficiency ϵ_ff as a free parameter, adjusted to encompass the data as shown in the figure. (Right) The “local” single-freefall model of M. R. Krumholz et al. (2012, KDM+2012) is shown for ϵ_ff = 0.01 (blue solid line) together with a scatter of ±0.15 dex (blue dashed lines) about the mean ϵ_ff value, as predicted by M. R. Krumholz & C. F. McKee (2020). The “local” model of B. Burkhart & P. Mocz (2019), which adds a power-law tail to the density PDF of the gas, is shown for two choices of the sonic Mach number M_s and the turbulence forcing parameter b (dark-red solid lines), for exponent α = 2 of the power law: top-left line for M_s = 20 and b = 0.3 and bottom-right line for M_s = 50 and b = 0.7. The prediction from the model of D. M. Salim et al. (2015, SFK2015), already introduced in Figure 11, is also shown (purple solid line).