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
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: To defend against criticisms of lack of rigor,
Yin distinguishes between single-case designs (used for unique or extreme cases) and multiple-case designs , which follow a "replication logic" to strengthen generalizability. Case study research : design and methods