Indirect standardisation (cont.)

The ratio of observed to expected deaths calculated in this way is called a standardised mortality ratio (SMR) tooltip link, and is usually multiplied by 100 and expressed as a percentage. So the SMR for Ecuador in this example is 152%.

This means that 52% more deaths are observed than we would expect if Ecuador had the same mortality pattern as Sweden.

Exercise

Interaction What do you think the SMR for Sweden would be using this calculation? Think about it, then click "answer" to find out.

Answer

 

The SMR for Sweden would be 100% in this calculation, because we are using the observed rates from Sweden as the standard, so in Sweden the observed number of deaths is the same as the expected number.

table solutions

Interpretation

The number of expected deaths calculated relates to what would happen if the country under study (Ecuador) had the same mortality experience tooltip link as the standard population (Sweden).

The ratio of the number of deaths observed in the study group or population to the number that would be expected if the study population had the same specific rates as the standard population. Usually expressed as a percentage.
Two populations have the same mortality experience if they have the same age-specific mortality rates.
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