A study’s overall dates do not describe every participant’s assessment period. When extracting an outcome from a research record, keep its own time frame with the named measurement. That prevents a calendar span from silently changing the meaning of the outcome.
ClinicalTrials.gov describes the outcome time-frame field as specific to the measurement and generally the participant’s assessment duration, rather than the entire study duration.
Use a four-field extraction line
Write the outcome’s title, metric description, time frame and source version together. Keep the exact period wording where needed for identification, but do not rewrite it into a stronger claim. A period beginning at a specified event needs that starting point to remain visible.
In a fictional example, an assessment at eight weeks and a study running across two calendar years describe different intervals. These are teaching time periods, not details of a real trial. Neither interval can be substituted for the other in a summary.
Check several outcomes separately
If a record lists more than one primary or secondary measurement, make one extraction line per measurement. Do not assume a common follow-up period merely because the outcomes appear on the same page. When two documents use different wording, preserve the difference and seek the report’s explanation.
Keep the record and result connected
A planned measurement description establishes what the record says will be assessed. A result needs a separately identified report and its analysis period. If linking the two, compare the outcome definition and time frame rather than matching only a familiar keyword.
A time-frame difference can change a research question, but this guide draws no conclusion about a named study. It makes no statement that an intervention works quickly, lasts for a particular period or should be used by a reader.
No live result was extracted. The practical aim is a source note that keeps measurement and period attached, leaving clinical appraisal to the evidence appropriate to that task.
Official field definitions read in the browser on 21 October 2026; the page states last update 24 April 2025. Editorial worksheets are suggested reading aids. No live trial or clinical outcome is appraised.
Primary source: ClinicalTrials.gov protocol registration data-element definitions. Related discussion: health information source quality.
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