Which design collects data across multiple time periods?

Which design collects data across multiple time periods?

• A. Longitudinal Design
• B. Cross-Sectional Design
• C. Experimental Design
• D. Case Study

Answer: (A)

Longitudinal designs involve collecting data from the same respondents (or units) at multiple time points, which lets researchers observe how things evolve over time and examine temporal relationships. By tracking change within the same individuals, you can see development, trajectories, and whether earlier factors predict later outcomes. For example, following a group of students from early schooling into adulthood can reveal how early skills influence later success. In contrast, a cross-sectional study collects data at a single point in time, so it captures a momentary snapshot rather than change; experimental designs focus on manipulating a variable under controlled conditions to test effects; and case studies provide an in-depth look at a single case or small number of cases, not inherently designed to track change across many periods.

Longitudinal designs involve collecting data from the same respondents (or units) at multiple time points, which lets researchers observe how things evolve over time and examine temporal relationships. By tracking change within the same individuals, you can see development, trajectories, and whether earlier factors predict later outcomes. For example, following a group of students from early schooling into adulthood can reveal how early skills influence later success. In contrast, a cross-sectional study collects data at a single point in time, so it captures a momentary snapshot rather than change; experimental designs focus on manipulating a variable under controlled conditions to test effects; and case studies provide an in-depth look at a single case or small number of cases, not inherently designed to track change across many periods.