Figure 2

Expected shapes of the observed distribution of survival times after detection. Shaded cells A1-C3 show the expected distribution of survival times after detection, given different scenarios for the true distribution of stage 1 survival (A, B and C) and incidence in the pre-detection period (1, 2 and 3). P = proportion of cases remaining in stage 1; t = time; * = exponential function $P(t)=e^{(-r_{1}t)}$, with mean stage 1 duration = 1/r_1; ** = linear function P(t) = -r ₁ t with fixed stage 1 duration = 1/r₁.