Cumulative SFE above a minimum column density $\left(N_{H_2}\right)$ contour as a function of column density for the CAFFEINE clouds. The pink and dark green curves indicate weighted averages over all significant cloud estimates above each $N_{H_2}$,with SFRs derived from YSOs and Hi-GAL protostellar clumps, respectively. The shaded areas indicate the corresponding statistical uncertainties (cf. Eq. 8). The dashed-dotted lines mark the standard deviations of the sample of cloud SFE estimates above each $N_{H_2}$. The red curve marks the weighted geometric average of the two methods for estimating the SFRs and SFEs.