We compare atomic gas , molecular gas , and the recent star formation rate ( SFR ) inferred from H \alpha in the Small Magellanic Cloud ( SMC ) . By using infrared dust emission and local dust-to-gas ratios , we construct a map of molecular gas that is independent of CO emission . This allows us to disentangle conversion factor effects from the impact of metallicity on the formation and star formation efficiency of molecular gas . On scales of 200 pc to 1 kpc ( where the distributions of H _ { 2 } and star formation match well ) we find a characteristic molecular gas depletion time of \tau _ { dep } ^ { mol } \sim 1.6 Gyr , similar to that observed in the molecule-rich parts of large spiral galaxies on similar spatial scales . This depletion time shortens on much larger scales to \sim 0.6 Gyr because of the presence of a diffuse H \alpha component , and lengthens on much smaller scales to \sim 7.5 Gyr because the H \alpha and H _ { 2 } distributions differ in detail . We estimate the systematic uncertainties in our dust-based \tau _ { dep } ^ { mol } measurement to be a factor of \sim 2 – 3 . We suggest that the impact of metallicity on the physics of star formation in molecular gas has at most this magnitude , rather than the factor of \sim 40 suggested by the ratio of SFR to CO emission . The relation between SFR and neutral ( \mbox { H$ { } _ { 2 } $ } + \mbox { H i } ) gas surface density is steep , with a power-law index \approx 2.2 \pm 0.1 , similar to that observed in the outer disks of large spiral galaxies . At a fixed total gas surface density the SMC has a 5 - 10 times lower molecular gas fraction ( and star formation rate ) than large spiral galaxies . We explore the ability of the recent models by and to reproduce our observations . We find that to explain our data at all spatial scales requires a low fraction of cold , gravitationally-bound gas in the SMC . We explore a combined model that incorporates both large scale thermal and dynamical equilibrium and cloud-scale photodissociation region structure and find that it reproduces our data well , as well as predicting a fraction of cold atomic gas very similar to that observed in the SMC .