Description
Return prevalence×(risk-1) divided by that denominator.
Epidemiological model terms link supplied prevalence, rates, durations or risk ratios under explicit assumptions. A mathematical identity or approximation does not estimate those inputs or establish the causal effect of an exposure.
Return prevalence×(risk-1) divided by that denominator.
When to use this tool
Use Population Attributable One Exposure Term when you need one transparent population-level model term.
How to use the tool and how it works
- Enter exposurePrevalence, relativeRisk. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read populationAttributableFraction. Use the output convention below.
Require exposurePrevalence in [0, 1], nonnegative relativeRisk and positive 1+prevalence×(risk-1). Return prevalence×(risk-1) divided by that denominator.1
The population-attributable expression combines exposure prevalence with relative risk. Its causal interpretation requires an appropriately justified exposure-risk relationship, not merely a numerical association.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| exposurePrevalence | Exposure Prevalence | Required. Finite number; minimum 0; maximum 1. |
| relativeRisk | Nonnegative supplied causal-model risk ratio, not an odds ratio automatically interchangeable with it. | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| populationAttributableFraction | Population Attributable Fraction | Required. Finite number. |
{
"input": {
"exposurePrevalence": 0.25,
"relativeRisk": 3
},
"output": {
"populationAttributableFraction": 0.3333333333333333
}
}Limitations and assumptions
- Protective risk below one can yield a negative fraction. Causal interpretation requires appropriate risk, exposure and confounding assumptions; this formula does not estimate a causal effect or support individual medical decisions.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use an appropriate epidemiological study and causal analysis for interpretation. Check steady-state assumptions, confounding, exposure definitions, compatible time units and uncertainty before applying a model term to health policy or individual care.
References
Similar or alternative tools
- Prevalence Incidence Duration Residual
Return incidence×duration and prevalence-minus-product residual.
- Direct Standardization One Stratum Term Tool
One directly standardized rate contribution; weights across all strata must sum to one externally.