Relative risk of death. The relative risk (RR) of death when the same treatment (FAIG+ATRA = FAIGA) was given in 2 separate trials is shown, adjusted for prognostic covariates. Values on the horizontal axis are RR of death with FAIGA as given in 1995 (trial A) compared to FAIGA as given in 1996-1998 (trial B). Values on the vertical axis are weights of the RR values determined by the data. The probability that survival is shorter in trial A (RR > 1), after accounting for prognostic covariates, is 0.87.