How should cases be chosen according to sampling size rules?

Choosing cases based on theory is a critical part of research design in methods and theory. The rationale stems from the need for a focused and systematic approach to case selection that aligns with the theoretical framework guiding the study. When cases are chosen according to theoretical considerations, it allows researchers to explore specific phenomena, test hypotheses derived from the theory, and examine patterns that are relevant to the theoretical constructs in question. This method ensures that the selected cases are likely to yield insights that contribute to the understanding of the theoretical issue being studied, which ultimately enhances the study’s validity and significance.

In contrast, other methods such as randomly selecting cases from the total population might not capture the nuances of the theory or address specific hypotheses effectively. Selecting cases solely based on hypotheses risks introducing bias or overlooking important variables that theory suggests should be considered. Choosing cases without regard to any background may lead to a lack of relevance and reduce the coherence of the research, making it harder to draw meaningful conclusions that relate to the theoretical framework. Thus, relying on theory provides a structured and purposeful strategy for case selection that supports deeper analysis and more robust findings.