Which of the following is considered an empirical material used in qualitative research?

Case studies are indeed considered an empirical material used in qualitative research. They involve an in-depth exploration of a particular instance, situation, or group over a period of time. This method allows researchers to gather detailed, contextual information and to gain insights into complex social phenomena. By focusing on the experiences and narratives of individuals or situations, case studies provide rich qualitative data that can help illuminate deeper understanding of social issues.

In qualitative research, the emphasis is typically placed on understanding the meanings and interpretations that participants assign to their experiences, and case studies are particularly effective in capturing these nuances. Researchers can analyze a variety of factors within a particular case, including interactions, environments, and the broader context, which can lead to valuable insights that might not emerge through quantitative methods alone.

Statistical data, textual analysis, and survey results, while important in broader research contexts, are generally more aligned with quantitative methodologies or analytical approaches rather than the distinctly qualitative focus of case studies.