What is a longitudinal study and its advantages?

• A. A longitudinal study follows the same participants over time to observe development and changes; advantages include capturing developmental trajectories but can be time-consuming and attrition-prone.
• B. A longitudinal study collects data at one time point only.
• C. A longitudinal study uses cross-sectional sampling.
• D. A longitudinal study is always quicker to complete than a cross-sectional study.

Answer: (A)