Description
Compare supplied dating anchors on a common research day index.
Pregnancy and birth research records distinguish observed and estimated values, dating anchors, day coordinates, time precision, clock offsets, and source permissions. A notation conversion or interval comparison does not determine a clinical date or validate consent. The supplied reference convention and uncertainty need to remain visible.
Compare supplied dating anchors on a common research day index.
When to use this tool
Use Pregnancy Study Dating Anchor Offset when you need this supplied research age, date, interval, clock, provenance, or record-rule calculation.
How to use the tool and how it works
- Enter firstAnchorDay, secondAnchorDay, observationDay. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read anchorDifferenceDays, firstRelativeDay, secondRelativeDay. Use the output convention below.
Return anchorDifferenceDays=secondAnchorDay-firstAnchorDay and each observation-relative day as observationDay minus the respective anchor.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| firstAnchorDay | First Anchor Day | Required. Safe integer. |
| secondAnchorDay | Second Anchor Day | Required. Safe integer. |
| observationDay | Observation Day | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| anchorDifferenceDays | Anchor Difference Days | Required. Safe integer. |
| firstRelativeDay | First Relative Day | Required. Safe integer. |
| secondRelativeDay | Second Relative Day | Required. Safe integer. |
{
"input": {
"firstAnchorDay": 100,
"secondAnchorDay": 103,
"observationDay": 190
},
"output": {
"anchorDifferenceDays": 3,
"firstRelativeDay": 90,
"secondRelativeDay": 87
}
}Limitations and assumptions
- Inputs are integer day coordinates on one basis. The tool compares supplied anchors without deciding which dating method is clinically correct, reconciling uncertain dates, or determining gestational age for care.
- 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 verified dates and sources together with the intended research or clinical assessment process. Check dating anchors, clock conventions, uncertainty, and whether a supplied reporting rule is appropriate for the question.
References
Similar or alternative tools
- Gestational Source Age Gap
Compare explicitly supplied research age records and civil-date elapsed time; no dating or care rule.
- Research Gestational Day Offset
Apply a supplied research day-anchor offset without pregnancy dating or clinical assessment.