Standardized incidence ratio

The standardized incidence ratio (SIR) or the standardized mortality ratio (SMR) quantifies the incidence or mortality rate of an observed cohort in relation to the total population. It is an indirect standardization procedure and indicates the ratio of the observed rate of events in the index population to the expected rate of events. The expected rate is calculated as , where the number of persons in the category in the index population and the corresponding category-specific event rate represents. ${\ displaystyle \ textstyle \ sum _ {i} n_ {i} R_ {i} \ displaystyle}$ ${\ displaystyle n_ {i}}$ ${\ displaystyle i}$ ${\ displaystyle R_ {i}}$

The age-specific incidence or mortality of a suitable comparison area is multiplied by the age-specific population figures of the study area and these are then summed up over the age groups, so that an expected number of cases is obtained. This is then related to the observed cases. For example, 8.3 leukemia cases would have been expected in the former municipality of Asse based on the leukemia frequency in the entire former administrative district of Braunschweig . 18 were observed, so that SIR = 18 / 8.3 = 2.17, i.e. 2.17 times the expected number of cases. A SIR of 1.0, such as B. observed in the area of the former joint municipality Schöppenstedt , means that exactly as many cases occurred as expected. The comparative figures should come from a comparable, but as large as possible region and the same years of illness.

Individual evidence

^ Gail, Mitchell H., Benichou, Jacques .: Encyclopedia of epidemiologic methods . John Wiley & Sons, Chichester 2000, ISBN 0-471-86641-5 , pp. 887 .
↑ Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety: Announcement of a statement with scientific justification by the Radiation Protection Commission (cancer frequency in the municipality of Asse from February 28 / March 1, 2013) from April 9, 2014 ( BAnz AT 03.03.2015 B3 ).

[1] Gail, Mitchell H., Benichou, Jacques .: Encyclopedia of epidemiologic methods . John Wiley & Sons, Chichester 2000, ISBN 0-471-86641-5 , pp. 887 .

[2] Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety: Announcement of a statement with scientific justification by the Radiation Protection Commission (cancer frequency in the municipality of Asse from February 28 / March 1, 2013) from April 9, 2014 ( BAnz AT 03.03.2015 B3 ).