In which type of research does data collection happen simultaneously across different groups?

Cross-sectional research is characterized by its approach to data collection, which occurs at a single point in time across various groups or segments. This method allows researchers to gather data from different individuals, demographics, or conditions simultaneously, providing a snapshot of the population or phenomena being studied. This simultaneous collection is efficient and particularly useful for identifying patterns, relationships, or differences among groups without the time commitment required for other types of research.

In contrast, longitudinal research involves collecting data from the same subjects over an extended period, which examines changes and developments over time. Action research focuses on collaborative problem-solving within specific settings, often through iterative cycles of reflection and data collection, not a simultaneous snapshot. Single-subject design emphasizes examining the behavior or outcomes of one individual or a small group over time, using repeated measures rather than simultaneous data gathering across multiple groups.