Description
Return overlap exposure with a supplied at-risk window.
Biostatistical terms depend on a declared observation unit, exposure denominator, event order and sampling design. A risk-set flag, paired discordance contribution or support-weight ratio can be computed locally without fitting a survival model, establishing a treatment effect or validating an inferential analysis.
Return overlap exposure with a supplied at-risk window.
When to use this tool
Use At Risk Window Entry Gap when checking the stated exposure, event, matched-pair or cluster-support convention.
How to use the tool and how it works
- Enter entry, windowStart, windowEnd, eventOrExit. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read eligibleStart, observedStop, atRiskDuration, delayedEntry. Use the output convention below.
Return overlap exposure with a supplied at-risk window. Require ordered window and eventOrExit >= entry; eligibleStart = max(entry,windowStart), observedStop = min(exit,windowEnd), duration = max(0,stop-start), delayedEntry = max(0,entry-windowStart).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| entry | Entry | Required. Finite number. |
| windowStart | Window Start | Required. Finite number. |
| windowEnd | Window End | Required. Finite number. |
| eventOrExit | Event Or Exit | Required. Finite number. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| eligibleStart | Eligible Start | Required. Finite number. |
| observedStop | Observed Stop | Required. Finite number. |
| atRiskDuration | max(0,observedStop-eligibleStart); zero can describe an empty or inverted interval. | Required. Finite number. |
| delayedEntry | Delayed Entry | Required. Finite number. |
{
"input": {
"entry": 3,
"windowStart": 0,
"windowEnd": 10,
"eventOrExit": 8
},
"output": {
"eligibleStart": 3,
"observedStop": 8,
"atRiskDuration": 5,
"delayedEntry": 3
}
}Limitations and assumptions
- Start can exceed stop with zero exposure; actual risk status, event observation and survival-model assumptions are not established.
- 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
Analyze complete verified data with a method appropriate to the design and censoring assumptions; assess uncertainty and consult qualified statistical and clinical professionals for health conclusions.
References
Similar or alternative tools
- Risk Set Left Entry Equality Flag
Check event-time inclusion in a supplied risk interval.
- Censored Event Riskset Flag
Return risk-set membership before or after exit events.