Description
Return positives/screened, confirmed/invited and confirmed/positive.
Epidemiological shares depend on who or what enters each denominator. Tests, distinct people, known-status records and eligible contacts describe different populations; a ratio computed from them is not automatically population risk or an individual diagnosis.
Return positives/screened, confirmed/invited and confirmed/positive.
When to use this tool
Use Screening Positive Yield Denominator Choice when you need a stated surveillance or screening count summary.
How to use the tool and how it works
- Enter positive, screened, invited, confirmed. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read screenPositivity, invitationYield, confirmedPositiveFraction. Use the output convention below.
Require positive invited, screened no greater than invited, positive tests no greater than screened and confirmations within positives. Return positives/screened, confirmed/invited and confirmed/positive.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| positive | Sign or comparison flag under the stated rule. | Required. Safe integer; minimum 1. |
| screened | Screened | Required. Safe integer; minimum 1. |
| invited | Invited | Required. Safe integer; minimum 1. |
| confirmed | Confirmed | Required. Safe integer; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| screenPositivity | Screen Positivity | Required. Finite number. |
| invitationYield | Invitation Yield | Required. Finite number. |
| confirmedPositiveFraction | Confirmed cases divided by screen-positive records; not sensitivity or specificity. | Required. Finite number. |
{
"input": {
"positive": 20,
"screened": 100,
"invited": 200,
"confirmed": 10
},
"output": {
"screenPositivity": 0.2,
"invitationYield": 0.05,
"confirmedPositiveFraction": 0.5
}
}Limitations and assumptions
- Zero positive tests is rejected under this contract. These denominator-specific yields are not sensitivity, specificity or individual diagnosis; verification and selection bias are not adjusted.
- 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 the appropriate study design and verified case definitions for health interpretation. Address ascertainment, repeated records, missing status, selection and uncertainty before generalizing a descriptive proportion.
References
Similar or alternative tools
- Test Positivity Repeated Person Exclusion
Count records or distinct people, with positive under any test or the first input occurrence as chosen.
- Secondary Attack Rate Index Exclusion
Bound secondary cases by that remainder and divide for secondary attack rate.