Qualitative content analysis of documents relating to different time periods, pertains to which of the following research designs ?

Qualitative content analysis of documents from different time periods belongs to a longitudinal design.

A cross-sectional design collects data at a single point in time and cannot capture change across periods.

A comparative design contrasts two or more cases rather than tracing one phenomenon over time.

An experimental design manipulates variables under controlled conditions, unlike document analysis.

The time dimension across successive documents is what makes the study longitudinal.

Content analysis systematically codes texts into categories to quantify or interpret their meaning.