RR and SIR

[R.Smart@unsw.edu.au (Richard Smart)]

Could someone please enlighten me as to the difference between Relative Risk
and Standardised Incidence Ratio as used in epidemiological studies.

As far as I can see, both are defined as (Observed number of cases) /
(Expected number of cases) . What am I missing?

Regards

Richard Smart PhD
Department of Nuclear Medicine
St. George Hospital
Kogarah, NSW 2217
Australia
Tel:61 2 350 3112
Fax:61 2 350 3991
Email:R.Smart@unsw.edu.au