Which of the following is NOT an advantage of cross-sectional design?

• A. Efficient
• B. Inexpensive (relative to longitudinal)
• C. Allow for large-scale data collection at a single time point
• D. Cannot infer causality/directionality

Answer: (D)

Cross-sectional designs measure variables at a single point in time, which makes them efficient and inexpensive compared with longitudinal studies. They also allow data to be collected from large numbers of participants at one time, providing a broad snapshot across groups. The trade-off is that temporal order and causality can’t be established from this design because you don’t track changes over time. That limitation means you can’t determine whether one variable causes changes in another or which variable came first. So the statement about not inferring causality/directionality is not an advantage; it’s a limitation of cross-sectional design.