What is a significant weakness of longitudinal studies?

Longitudinal studies involve collecting data from the same subjects over an extended period of time, which allows researchers to analyze changes and developments over time. However, one significant weakness of this approach is attrition, which refers to the loss of participants throughout the study. As time goes on, participants may drop out for various reasons, such as losing interest, moving away, health issues, or other life changes. This can lead to a biased sample if the individuals who drop out differ significantly from those who remain in the study, potentially skewing the results and limiting the generalizability of the findings.

This impact of attrition is especially concerning during lengthy studies, where sustained engagement is crucial. It can hinder the reliability of the conclusions drawn from the research, as the final participant group may not be representative of the original population. In contrast, other options do not represent significant weaknesses of longitudinal studies, as they either highlight strengths or misunderstand the nature of the data collection process involved in these studies.