Panel studies are research methods that involve collecting data from the same subjects, known as a panel, over multiple time periods. This approach allows researchers to track changes and trends in behaviors, opinions, or characteristics within the same group, providing valuable insights into how these elements evolve over time. These studies are commonly used in fields like sociology, psychology, and market research. By analyzing the repeated measures from the same individuals, researchers can better understand causal relationships and the impact of specific events or interventions on the panel members' responses.