Description
Sum nonnegative personTime for atRisk entries into atRiskTime, and for entries with both atRisk and observed into observedRiskTime; the arrays must have equal lengths.
Epidemiological records have both an observation basis and a resolution. The share of at-risk time supported by observations differs from disease frequency, while a source's stated time quantum describes resolution rather than measured accuracy.
Sum nonnegative personTime for atRisk entries into atRiskTime, and for entries with both atRisk and observed into observedRiskTime; the arrays must have equal lengths.
When to use this tool
Use Person Time Risk Support Share when checking observation support or source resolution under an explicit selection mask.
How to use the tool and how it works
- Enter personTime, atRisk, observed. Keep parallel arrays aligned. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read atRiskTime, observedRiskTime, share, defined. Inspect defined before interpreting the associated values.
Sum nonnegative personTime for atRisk entries into atRiskTime, and for entries with both atRisk and observed into observedRiskTime; the arrays must have equal lengths. Return share = observedRiskTime/atRiskTime when the denominator is positive, otherwise share = 0 and defined = false. All durations must use one time unit; share is dimensionless.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| personTime | Nonnegative per-record durations on one common person-time unit basis. | Required. Array of finite number; minimum 0; maximum items 256. |
| atRisk | Per-record flags selecting time at risk. | Required. Array of boolean; maximum items 256. |
| observed | Position-aligned flags identifying which supplied records are observed. | Required. Array of boolean; maximum items 256. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| atRiskTime | Sum of durations whose atRisk flag is true. | Required. Finite number. |
| observedRiskTime | Sum of durations whose atRisk and observed flags are both true. | Required. Finite number. |
| share | Dimensionless selected contribution divided by the stated total; not a percentage. | Required. Finite number. |
| defined | Whether the denominator is positive and the returned ratio is defined; inspect this before using a zero placeholder. | Required. Boolean. |
{
"input": {
"personTime": [
2,
3,
5
],
"atRisk": [
true,
true,
false
],
"observed": [
true,
false,
true
]
},
"output": {
"atRiskTime": 5,
"observedRiskTime": 2,
"share": 0.4,
"defined": true
}
}Limitations and assumptions
- This measures observation support within supplied at-risk time, not disease risk, incidence or representativeness. A zero placeholder with defined = false is not evidence of complete absence of observation bias.
- 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
Inspect the original follow-up and source records before treating coverage or precision summaries as evidence of unbiased surveillance.
References
Similar or alternative tools
- Sample Support Volume Fraction
Sum each array and return fraction = supportedVolume/totalVolume when totalVolume > 0, otherwise fraction = 0 and defined = false.
- Person Time Entry Exit Overlap Tool
Calculate supplied person-risk interval overlap with a half-open observation window without determining disease-free eligibility.