In a panel study, what is the main characteristic of the data collected?

In a panel study, the main characteristic of the data collected is that it is gathered at multiple time points from the same individuals. This approach allows researchers to observe changes over time within the same subjects, which can provide insights into trends, causal relationships, and the dynamics of social phenomena. By repeatedly measuring the same respondents, researchers can assess how variables evolve, what factors influence change, and how different experiences may affect outcomes over time.

This longitudinal aspect is crucial because it enables a deeper understanding of processes that cross time, as opposed to simply capturing a snapshot at a single moment. Such studies are instrumental in fields like social sciences, marketing research, and public health, where understanding the temporal aspect of behavior is essential for effective analysis and implications.

The other options do not accurately reflect the nature of panel studies. Specifically, data collected not being from the same individuals and data being collected only once would describe cross-sectional studies rather than panel studies. Analyzing data in real-time pertains more to other research designs that involve immediate data collection and analysis, rather than the structured, longitudinal focus of a panel study.