[Mortality: various measurements compared].

SMR (Standardized Mortality Ratio) is a useful epidemiological measure but it cannot be computed when person-years distributions (denominators) are not available. In this situation PMR (Proportionate Mortality Ratio) and MOR (Mortality Odds Ratio) represent possible alternatives. Definitions of PMR and MOR are presented, and properties and drawbacks of these measures are discussed in relation to SMR's estimates. Fictitious data representing factual situations are used as working examples.