Which is a disadvantage of longitudinal design?

• A. Time consuming
• B. Attrition bias
• C. Heavy on resources
• D. Efficient data collection

Answer: (A)

Longitudinal designs involve repeatedly measuring the same individuals over time to observe how things change. The key drawback is the extended time frame needed to collect all the data, often spanning months or years. This means researchers must keep participants engaged across multiple waves, coordinate follow-ups, and secure funding and resources for a long period, which slows the overall research process and delays findings. While issues like participants dropping out (attrition) and high resource demands are real challenges in longitudinal work, the most defining disadvantage in many contexts is simply how time-intensive the data collection becomes.