Description
Count inclusive person-days inside two supplied calendar intervals.
Medication-study records distinguish supplied coverage intervals, observed person-days, dispensing reversals and source event definitions. Inclusive calendar-day counting differs from continuous elapsed time. Recorded supply and washout flags are study conventions rather than evidence of ingestion, drug clearance, causal effect or suitable treatment.
Count inclusive person-days inside two supplied calendar intervals.
When to use this tool
Use Drug Study Person Day Contribution when you already have observedStartDate, observedEndDate, windowStartDate, windowEndDate and need to count inclusive person-days inside two supplied calendar intervals.
How to use the tool and how it works
- Enter observedStartDate, observedEndDate, windowStartDate, windowEndDate. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read inclusivePersonDays. Use the output convention below.
Parse real UTC dates and require each end>=start; return max(0,min(ends)-max(starts) in days+1).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| observedStartDate | Observed Start Date | Required. Text; maximum UTF-16 length 8192. Real proleptic Gregorian YYYY-MM-DD; four-digit years 0000-9999 accepted. |
| observedEndDate | Observed End Date | Required. Text; maximum UTF-16 length 8192. Real proleptic Gregorian YYYY-MM-DD; four-digit years 0000-9999 accepted. |
| windowStartDate | Window Start Date | Required. Text; maximum UTF-16 length 8192. Real proleptic Gregorian YYYY-MM-DD; four-digit years 0000-9999 accepted. |
| windowEndDate | Window End Date | Required. Text; maximum UTF-16 length 8192. Real proleptic Gregorian YYYY-MM-DD; four-digit years 0000-9999 accepted. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| inclusivePersonDays | Inclusive overlap count; a shared endpoint contributes one day. | Required. Safe integer. |
{
"input": {
"observedStartDate": "2026-10-28",
"observedEndDate": "2026-11-05",
"windowStartDate": "2026-11-01",
"windowEndDate": "2026-11-30"
},
"output": {
"inclusivePersonDays": 5
}
}Limitations and assumptions
- A shared endpoint contributes one day; this calendar count is not continuous elapsed time, verified exposure or an epidemiological causal estimate.
- 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.
Alternative or Complementary methods
Construct exposure episodes from a documented study rule and verified dispensing or observation history. Keep inclusive calendar coverage distinct from elapsed time and actual ingestion; evaluate causal questions with a complete study design rather than one interval flag.
References
Similar or alternative tools
- Drug Study Index Date Offset
Measure signed days from a drug study's supplied index date.
- Prescription Coverage End Date
Calculate an inclusive supply end date from supplied start and day count.