Figure 5. The initial growth rate, q_n, versus population density for the PSD dataset with more than 20 infections (not shown is the outlier Kissidougou, Guinea, with a population density of 34 individuals per kilometer, and a growth rate of 0.41 days⁻¹), where error bars are standard deviations.

We find that the initial growth rate drops significantly with population density (Spearman ρ = −0.48, p < 10⁻³, n = 44).