How to determine the target group for research and select samples?

Determining the target population involves precisely defining the group possessing the characteristics central to the research question, while sample selection identifies a subset for feasible study. This process must ensure the sample sufficiently represents the target group to enable valid inferences about the entire population, balancing practical constraints like accessibility and resources with scientific rigor. Clear definition of inclusion and exclusion criteria delimits the target population. Selection hinges on the chosen sampling strategy: probability methods (e.g., random, stratified, cluster) enable statistical generalizability through random selection, whereas non-probability approaches (e.g., convenience, purposive, quota) are pragmatic but limit extrapolation. Essential considerations include sample size determination via power analysis or confidence intervals, access constraints, ethical clearance requirements regarding participant recruitment, and minimizing selection biases throughout the process. Commence by explicitly aligning the target group with the research objectives and questions. Define specific parameters (e.g., age, diagnosis, location, behavior). Choose a sampling strategy based on resource availability, accessibility of the population, and the desired level of generalizability. Implement the selected method consistently, ensuring participant recruitment adheres to ethical guidelines. Effective selection underpins research validity, strengthens confidence in findings, enables resource optimization, and facilitates meaningful contributions to knowledge within the studied domain.