Editorial essay · time
Longitudinal
outcomes
Why change over time is harder to measure—and more useful to understand—than a single before-and-after result.
Time is part of the evidence.
Months and years can reveal durability, delayed outcomes, attrition, and whether a measured change matters outside the study visit. They can also introduce new sources of bias and missing data.
Ask what was measured at each point, who remained in the study, and whether the comparison stayed meaningful. A baseline is a reference point, not a personal target.
Read the Research Library, the first research window, and the bone density note.