Standardized Mortality Ratio (SMR): Observed Over Expected
Standardized mortality or incidence ratio: observed events over the expected count.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Observed events
- 30
- Strata, one per line
- 10000, 0.001 5000, 0.002
Result: SMR 1.5: 30 observed ÷ 20 expected
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Observed events
- Expected events (or enter strata below)
- Strata, one per line: person-time, reference rate
How this is calculated
Citation
Stated arithmetic: observed events over the expected count, the expected count being the reference rates applied to the study population's person-time (indirect standardization). No interval is computed.
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.