Researchers are encouraged to use triangulation by drawing from six sources of evidence: documentation, archival records, interviews, direct observations, participant-observation, and physical artifacts.
Typically "how" or "why" questions that explore contemporary phenomena within their real-life context. Case study research : design and methods
To defend against criticisms of lack of rigor, Yin offers four tests for quality: construct validity , internal validity , external validity , and reliability . Analytic and Reporting Strategies Researchers are encouraged to use triangulation by drawing
Establishing the standards for evaluating the results, such as identifying patterns or commonalities. Methodological Framework Case study research : design and methods
The book outlines a linear but iterative process for conducting research: