Description
Count inclusive overlap days between prior supply end and next supply start.
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 overlap days between prior supply end and next supply start.
When to use this tool
Use Refill Overlap Days when you already have earlierCoverageEndDate, nextSupplyStartDate and need to count inclusive overlap days between prior supply end and next supply start.
How to use the tool and how it works
- Enter earlierCoverageEndDate, nextSupplyStartDate. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read overlapDays. Use the output convention below.
Parse real UTC dates; return max(0,earlierEnd-nextStart in days+1).1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| earlierCoverageEndDate | Earlier Coverage End Date | Required. Text; maximum UTF-16 length 8192. Real proleptic Gregorian YYYY-MM-DD; four-digit years 0000-9999 accepted. |
| nextSupplyStartDate | Next Supply Start 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 |
|---|---|---|
| overlapDays | max(0,prior inclusive end-next start+1); same-day boundaries count one day. | Required. Safe integer. |
{
"input": {
"earlierCoverageEndDate": "2026-11-05",
"nextSupplyStartDate": "2026-11-03"
},
"output": {
"overlapDays": 3
}
}Limitations and assumptions
- Same-day boundaries count one overlap day; supplied coverage is not actual ingestion, adherence, concurrent dosing or a recommendation.
- 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
- Prescription Coverage End Date
Calculate an inclusive supply end date from supplied start and day count.
- Drug Study Person Day Contribution
Count inclusive person-days inside two supplied calendar intervals.