Which method involves gathering detailed information from observation and interviews focused on one or a few participants?

The method that involves gathering detailed information from observation and interviews focused on one or a few participants is known as a case study. This approach allows researchers to delve deeply into the unique circumstances and experiences of individuals, providing rich, qualitative data that can reveal insights that may not be captured through broader research methods.

Case studies are particularly valuable in educational and psychological settings, where understanding the nuances of a participant's thoughts, behaviors, and context can inform effective interventions and strategies. By concentrating on a limited number of subjects, researchers can explore complex issues in depth, making connections between various factors that influence the participants' situations.

In contrast, a field study generally involves observing subjects in their natural environment but may focus more broadly and not on the in-depth interactions tied to individual participants. Survey research tends to gather information from a larger group through questionnaires or surveys, focusing on quantifiable data rather than the detailed exploratory findings typical of case studies. Experimental design involves manipulating variables to establish cause-and-effect relationships, which differs significantly from the qualitative, exploratory nature of a case study.