Figure 1.

Illustration of the notation. Thick segments: four careers as FSW, with the portion of career without condom use in red and the portion of career with condom use in black. The lengths of the double arrows are the values of the variables $C_{\mathsf{i}}$, ${\tilde{C}}_{\mathsf{i}}$, $F_{\mathsf{i}}$, ${\tilde{F}}_{\mathsf{i}}$, when applicable. Vertical dashed lines are drawn at the time of sampling (τ) and at the time of the intervention ($t_0$).