To calculate initial exposed to risk, why adding the sum (1-ti) (i.e. residual duration of ith life who died at ti) to the central exposed to risk.
Because this is the difference in their definitions. Both sum b-a across censored lives, no difference Initial EtR sums 1-a across deaths, central EtR sums t-a across deaths So, that's an extra 1-t per life in the initial EtR Good luck! John
