longitudinally.

1. Through observations or analysis extending across a period of time.

2. Along the length or principal long axis of an object rather than across it.

Use it for

Words that belong together

• longitudinally assess
• longitudinally collected data

On the page

The participants were assessed longitudinally over three years.

The data were analyzed longitudinally rather than treated as unrelated snapshots.

Usage notes

Primary category: academic / formal. Forms: Invariable adverb; no plural or tense forms. Comparison is used only where a particular degree naturally permits it. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: inference, qualification, analysis, methodology. Disciplines: academic writing, reasoning, research. Commonness: moderately common.