Fig. 2
Risk ratios estimated by Poisson model (RRP) by varying the shape parameter of the Weibull distribution for generating survival times, that is by moving from scenario A to scenario B (left panel) and from scenario A to scenario C (right panel) The left panel was obtained by assuming that survival times followed a Weibull distribution with λ = 0.75 and υ ϵ (0.1,1). The right panel was obtained by assuming that survival times followed a Weibull distribution with λ = 0.1 and υ ϵ (1,3). The true exposure effect (RRT) was set to 0.75