Estimation of standardized mortality ratio with missing death certificates

In epidemiological studies, interest often lies in comparing the mortality rate of acertain cohort to that of a standard population; a standard summary statistic in this regard is the standardized mortality ratio (SMR). Traditionally, the observed number of events is assumed to have Poisson distribution. Thus, inference procedures for the SMR can be formulated based on those for the Poisson distribution. given by SMR = O/E, where O is the number of deaths observed in the cohort from specified causes and the expected number E is calculated from person years in the cohort and mortality rates from a reference population. While person years can easily be calculated from the cohort and reference rates are generally available from statistical offices or World Health Organization, problems can arise with the accessibility of the causes of death of the deceased study participants. s paper, the problem of missing certificates, studied by Rittgen and Becker [1] is revisited.The model assumptions are modified and the effect of this modification is investigated.